diff --git a/pkg/dev_compiler/tool/dart2js_nnbd_sdk_error_golden.txt b/pkg/dev_compiler/tool/dart2js_nnbd_sdk_error_golden.txt
index 3daf984bedc..d689db50e3f 100644
--- a/pkg/dev_compiler/tool/dart2js_nnbd_sdk_error_golden.txt
+++ b/pkg/dev_compiler/tool/dart2js_nnbd_sdk_error_golden.txt
@@ -13,159 +13,12 @@ ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/h
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/http.dart|1541|8|14|Non-nullable instance field 'autoUncompress' must be initialized.
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/http.dart|171|8|12|Non-nullable instance field 'autoCompress' must be initialized.
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/http.dart|990|10|4|Non-nullable instance field 'name' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|17637|15|4|Non-nullable instance field 'body' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19492|10|7|Non-nullable instance field 'dirName' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19508|10|7|Non-nullable instance field 'dirName' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19568|10|12|Non-nullable instance field 'autocomplete' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19570|8|9|Non-nullable instance field 'autofocus' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19574|7|9|Non-nullable instance field 'maxLength' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19576|8|8|Non-nullable instance field 'multiple' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19578|10|7|Non-nullable instance field 'pattern' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19580|10|11|Non-nullable instance field 'placeholder' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19582|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19584|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19586|7|4|Non-nullable instance field 'size' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19633|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19635|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19637|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19654|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19656|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19658|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19675|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19677|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19679|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19696|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19698|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19700|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19719|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19721|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19738|10|11|Non-nullable instance field 'placeholder' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19740|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19742|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19776|8|7|Non-nullable instance field 'checked' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19778|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19795|8|7|Non-nullable instance field 'checked' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19797|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19806|10|6|Non-nullable instance field 'accept' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19808|8|8|Non-nullable instance field 'multiple' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19810|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19821|10|10|Non-nullable instance field 'formAction' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19823|10|11|Non-nullable instance field 'formEnctype' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19825|10|10|Non-nullable instance field 'formMethod' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19827|8|14|Non-nullable instance field 'formNoValidate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19829|10|10|Non-nullable instance field 'formTarget' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19839|10|3|Non-nullable instance field 'alt' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19841|10|10|Non-nullable instance field 'formAction' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19843|10|11|Non-nullable instance field 'formEnctype' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19845|10|10|Non-nullable instance field 'formMethod' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19847|8|14|Non-nullable instance field 'formNoValidate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19849|10|10|Non-nullable instance field 'formTarget' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19851|7|6|Non-nullable instance field 'height' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19853|10|3|Non-nullable instance field 'src' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19855|7|5|Non-nullable instance field 'width' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4194|10|11|Non-nullable instance field '_background' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4206|10|21|Non-nullable instance field '_backgroundAttachment' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4218|10|16|Non-nullable instance field '_backgroundColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4230|10|16|Non-nullable instance field '_backgroundImage' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4242|10|19|Non-nullable instance field '_backgroundPosition' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4254|10|17|Non-nullable instance field '_backgroundRepeat' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4266|10|7|Non-nullable instance field '_border' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4278|10|13|Non-nullable instance field '_borderBottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4290|10|18|Non-nullable instance field '_borderBottomColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4302|10|18|Non-nullable instance field '_borderBottomStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4314|10|18|Non-nullable instance field '_borderBottomWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4326|10|15|Non-nullable instance field '_borderCollapse' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4338|10|12|Non-nullable instance field '_borderColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4350|10|11|Non-nullable instance field '_borderLeft' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4362|10|16|Non-nullable instance field '_borderLeftColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4374|10|16|Non-nullable instance field '_borderLeftStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4386|10|16|Non-nullable instance field '_borderLeftWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4398|10|12|Non-nullable instance field '_borderRight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4410|10|17|Non-nullable instance field '_borderRightColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4422|10|17|Non-nullable instance field '_borderRightStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4434|10|17|Non-nullable instance field '_borderRightWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4446|10|14|Non-nullable instance field '_borderSpacing' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4458|10|12|Non-nullable instance field '_borderStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4470|10|10|Non-nullable instance field '_borderTop' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4482|10|15|Non-nullable instance field '_borderTopColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4494|10|15|Non-nullable instance field '_borderTopStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4506|10|15|Non-nullable instance field '_borderTopWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4518|10|12|Non-nullable instance field '_borderWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4530|10|7|Non-nullable instance field '_bottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4542|10|12|Non-nullable instance field '_captionSide' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4554|10|6|Non-nullable instance field '_clear' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4566|10|5|Non-nullable instance field '_clip' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4578|10|6|Non-nullable instance field '_color' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4590|10|8|Non-nullable instance field '_content' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4602|10|7|Non-nullable instance field '_cursor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4614|10|10|Non-nullable instance field '_direction' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4626|10|8|Non-nullable instance field '_display' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4638|10|11|Non-nullable instance field '_emptyCells' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4650|10|5|Non-nullable instance field '_font' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4662|10|11|Non-nullable instance field '_fontFamily' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4674|10|9|Non-nullable instance field '_fontSize' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4686|10|10|Non-nullable instance field '_fontStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4698|10|12|Non-nullable instance field '_fontVariant' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4710|10|11|Non-nullable instance field '_fontWeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4722|10|7|Non-nullable instance field '_height' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4734|10|5|Non-nullable instance field '_left' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4746|10|14|Non-nullable instance field '_letterSpacing' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4758|10|11|Non-nullable instance field '_lineHeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4770|10|10|Non-nullable instance field '_listStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4782|10|15|Non-nullable instance field '_listStyleImage' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4794|10|18|Non-nullable instance field '_listStylePosition' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4806|10|14|Non-nullable instance field '_listStyleType' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4818|10|7|Non-nullable instance field '_margin' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4830|10|13|Non-nullable instance field '_marginBottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4842|10|11|Non-nullable instance field '_marginLeft' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4854|10|12|Non-nullable instance field '_marginRight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4866|10|10|Non-nullable instance field '_marginTop' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4878|10|10|Non-nullable instance field '_maxHeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4890|10|9|Non-nullable instance field '_maxWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4902|10|10|Non-nullable instance field '_minHeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4914|10|9|Non-nullable instance field '_minWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4926|10|8|Non-nullable instance field '_outline' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4938|10|13|Non-nullable instance field '_outlineColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4950|10|13|Non-nullable instance field '_outlineStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4962|10|13|Non-nullable instance field '_outlineWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4974|10|9|Non-nullable instance field '_overflow' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4986|10|8|Non-nullable instance field '_padding' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4998|10|14|Non-nullable instance field '_paddingBottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5010|10|12|Non-nullable instance field '_paddingLeft' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5022|10|13|Non-nullable instance field '_paddingRight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5034|10|11|Non-nullable instance field '_paddingTop' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5046|10|15|Non-nullable instance field '_pageBreakAfter' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5058|10|16|Non-nullable instance field '_pageBreakBefore' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5070|10|16|Non-nullable instance field '_pageBreakInside' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5082|10|9|Non-nullable instance field '_position' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5094|10|7|Non-nullable instance field '_quotes' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5106|10|6|Non-nullable instance field '_right' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5118|10|12|Non-nullable instance field '_tableLayout' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5130|10|10|Non-nullable instance field '_textAlign' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5142|10|15|Non-nullable instance field '_textDecoration' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5154|10|11|Non-nullable instance field '_textIndent' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5166|10|14|Non-nullable instance field '_textTransform' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5178|10|4|Non-nullable instance field '_top' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5190|10|12|Non-nullable instance field '_unicodeBidi' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5202|10|14|Non-nullable instance field '_verticalAlign' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5214|10|11|Non-nullable instance field '_visibility' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5226|10|11|Non-nullable instance field '_whiteSpace' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5238|10|6|Non-nullable instance field '_width' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5250|10|12|Non-nullable instance field '_wordSpacing' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5262|10|7|Non-nullable instance field '_zIndex' must be initialized.
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/io/io.dart|5589|12|8|Non-nullable instance field 'encoding' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/svg/dart2js/svg_dart2js.dart|4153|7|10|Non-nullable instance field 'zoomAndPan' must be initialized.
 ERROR|STATIC_TYPE_WARNING|UNDEFINED_OPERATOR|lib/_internal/js_runtime/lib/interceptors.dart|1654|28|1|The operator '&' isn't defined for the type 'JSInt'.
 ERROR|STATIC_TYPE_WARNING|UNDEFINED_OPERATOR|lib/_internal/js_runtime/lib/interceptors.dart|1656|27|1|The operator '&' isn't defined for the type 'JSInt'.
 ERROR|STATIC_TYPE_WARNING|UNDEFINED_OPERATOR|lib/_internal/js_runtime/lib/interceptors.dart|1659|17|1|The operator '&' isn't defined for the type 'JSInt'.
 ERROR|STATIC_TYPE_WARNING|UNDEFINED_OPERATOR|lib/_internal/js_runtime/lib/interceptors.dart|1664|18|1|The operator '&' isn't defined for the type 'JSInt'.
 ERROR|STATIC_TYPE_WARNING|UNDEFINED_OPERATOR|lib/_internal/js_runtime/lib/interceptors.dart|1664|44|1|The operator '&' isn't defined for the type 'JSInt'.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/html/dart2js/html_dart2js.dart|20081|13|7|The final variable 'keyCode' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/html/dart2js/html_dart2js.dart|20083|13|8|The final variable 'charCode' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/html/dart2js/html_dart2js.dart|21655|17|9|The final variable '_get_data' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/indexed_db/dart2js/indexed_db_dart2js.dart|1304|23|6|The final variable 'target' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/web_gl/dart2js/web_gl_dart2js.dart|89|23|6|The final variable 'canvas' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/web_gl/dart2js/web_gl_dart2js.dart|92|25|15|The final variable 'offscreenCanvas' must be initialized.
 WARNING|STATIC_WARNING|DEAD_NULL_AWARE_EXPRESSION|lib/_http/http.dart|1476|39|5|The left operand can't be null, so the right operand is never executed.
 WARNING|STATIC_WARNING|DEAD_NULL_AWARE_EXPRESSION|lib/_http/http.dart|8384|60|5|The left operand can't be null, so the right operand is never executed.
 WARNING|STATIC_WARNING|DEAD_NULL_AWARE_EXPRESSION|lib/_http/http.dart|9311|54|5|The left operand can't be null, so the right operand is never executed.
diff --git a/pkg/dev_compiler/tool/dartdevc_nnbd_sdk_error_golden.txt b/pkg/dev_compiler/tool/dartdevc_nnbd_sdk_error_golden.txt
index 3c217085f1d..9fc6d718e90 100644
--- a/pkg/dev_compiler/tool/dartdevc_nnbd_sdk_error_golden.txt
+++ b/pkg/dev_compiler/tool/dartdevc_nnbd_sdk_error_golden.txt
@@ -22,154 +22,7 @@ ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/h
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/http.dart|1541|8|14|Non-nullable instance field 'autoUncompress' must be initialized.
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/http.dart|171|8|12|Non-nullable instance field 'autoCompress' must be initialized.
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/_http/http.dart|990|10|4|Non-nullable instance field 'name' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|17637|15|4|Non-nullable instance field 'body' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19492|10|7|Non-nullable instance field 'dirName' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19508|10|7|Non-nullable instance field 'dirName' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19568|10|12|Non-nullable instance field 'autocomplete' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19570|8|9|Non-nullable instance field 'autofocus' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19574|7|9|Non-nullable instance field 'maxLength' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19576|8|8|Non-nullable instance field 'multiple' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19578|10|7|Non-nullable instance field 'pattern' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19580|10|11|Non-nullable instance field 'placeholder' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19582|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19584|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19586|7|4|Non-nullable instance field 'size' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19633|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19635|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19637|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19654|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19656|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19658|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19675|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19677|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19679|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19696|12|11|Non-nullable instance field 'valueAsDate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19698|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19700|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19719|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19721|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19738|10|11|Non-nullable instance field 'placeholder' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19740|8|8|Non-nullable instance field 'readOnly' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19742|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19776|8|7|Non-nullable instance field 'checked' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19778|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19795|8|7|Non-nullable instance field 'checked' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19797|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19806|10|6|Non-nullable instance field 'accept' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19808|8|8|Non-nullable instance field 'multiple' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19810|8|8|Non-nullable instance field 'required' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19821|10|10|Non-nullable instance field 'formAction' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19823|10|11|Non-nullable instance field 'formEnctype' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19825|10|10|Non-nullable instance field 'formMethod' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19827|8|14|Non-nullable instance field 'formNoValidate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19829|10|10|Non-nullable instance field 'formTarget' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19839|10|3|Non-nullable instance field 'alt' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19841|10|10|Non-nullable instance field 'formAction' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19843|10|11|Non-nullable instance field 'formEnctype' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19845|10|10|Non-nullable instance field 'formMethod' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19847|8|14|Non-nullable instance field 'formNoValidate' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19849|10|10|Non-nullable instance field 'formTarget' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19851|7|6|Non-nullable instance field 'height' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19853|10|3|Non-nullable instance field 'src' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|19855|7|5|Non-nullable instance field 'width' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4194|10|11|Non-nullable instance field '_background' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4206|10|21|Non-nullable instance field '_backgroundAttachment' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4218|10|16|Non-nullable instance field '_backgroundColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4230|10|16|Non-nullable instance field '_backgroundImage' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4242|10|19|Non-nullable instance field '_backgroundPosition' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4254|10|17|Non-nullable instance field '_backgroundRepeat' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4266|10|7|Non-nullable instance field '_border' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4278|10|13|Non-nullable instance field '_borderBottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4290|10|18|Non-nullable instance field '_borderBottomColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4302|10|18|Non-nullable instance field '_borderBottomStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4314|10|18|Non-nullable instance field '_borderBottomWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4326|10|15|Non-nullable instance field '_borderCollapse' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4338|10|12|Non-nullable instance field '_borderColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4350|10|11|Non-nullable instance field '_borderLeft' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4362|10|16|Non-nullable instance field '_borderLeftColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4374|10|16|Non-nullable instance field '_borderLeftStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4386|10|16|Non-nullable instance field '_borderLeftWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4398|10|12|Non-nullable instance field '_borderRight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4410|10|17|Non-nullable instance field '_borderRightColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4422|10|17|Non-nullable instance field '_borderRightStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4434|10|17|Non-nullable instance field '_borderRightWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4446|10|14|Non-nullable instance field '_borderSpacing' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4458|10|12|Non-nullable instance field '_borderStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4470|10|10|Non-nullable instance field '_borderTop' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4482|10|15|Non-nullable instance field '_borderTopColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4494|10|15|Non-nullable instance field '_borderTopStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4506|10|15|Non-nullable instance field '_borderTopWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4518|10|12|Non-nullable instance field '_borderWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4530|10|7|Non-nullable instance field '_bottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4542|10|12|Non-nullable instance field '_captionSide' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4554|10|6|Non-nullable instance field '_clear' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4566|10|5|Non-nullable instance field '_clip' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4578|10|6|Non-nullable instance field '_color' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4590|10|8|Non-nullable instance field '_content' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4602|10|7|Non-nullable instance field '_cursor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4614|10|10|Non-nullable instance field '_direction' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4626|10|8|Non-nullable instance field '_display' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4638|10|11|Non-nullable instance field '_emptyCells' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4650|10|5|Non-nullable instance field '_font' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4662|10|11|Non-nullable instance field '_fontFamily' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4674|10|9|Non-nullable instance field '_fontSize' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4686|10|10|Non-nullable instance field '_fontStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4698|10|12|Non-nullable instance field '_fontVariant' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4710|10|11|Non-nullable instance field '_fontWeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4722|10|7|Non-nullable instance field '_height' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4734|10|5|Non-nullable instance field '_left' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4746|10|14|Non-nullable instance field '_letterSpacing' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4758|10|11|Non-nullable instance field '_lineHeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4770|10|10|Non-nullable instance field '_listStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4782|10|15|Non-nullable instance field '_listStyleImage' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4794|10|18|Non-nullable instance field '_listStylePosition' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4806|10|14|Non-nullable instance field '_listStyleType' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4818|10|7|Non-nullable instance field '_margin' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4830|10|13|Non-nullable instance field '_marginBottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4842|10|11|Non-nullable instance field '_marginLeft' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4854|10|12|Non-nullable instance field '_marginRight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4866|10|10|Non-nullable instance field '_marginTop' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4878|10|10|Non-nullable instance field '_maxHeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4890|10|9|Non-nullable instance field '_maxWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4902|10|10|Non-nullable instance field '_minHeight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4914|10|9|Non-nullable instance field '_minWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4926|10|8|Non-nullable instance field '_outline' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4938|10|13|Non-nullable instance field '_outlineColor' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4950|10|13|Non-nullable instance field '_outlineStyle' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4962|10|13|Non-nullable instance field '_outlineWidth' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4974|10|9|Non-nullable instance field '_overflow' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4986|10|8|Non-nullable instance field '_padding' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|4998|10|14|Non-nullable instance field '_paddingBottom' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5010|10|12|Non-nullable instance field '_paddingLeft' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5022|10|13|Non-nullable instance field '_paddingRight' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5034|10|11|Non-nullable instance field '_paddingTop' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5046|10|15|Non-nullable instance field '_pageBreakAfter' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5058|10|16|Non-nullable instance field '_pageBreakBefore' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5070|10|16|Non-nullable instance field '_pageBreakInside' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5082|10|9|Non-nullable instance field '_position' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5094|10|7|Non-nullable instance field '_quotes' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5106|10|6|Non-nullable instance field '_right' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5118|10|12|Non-nullable instance field '_tableLayout' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5130|10|10|Non-nullable instance field '_textAlign' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5142|10|15|Non-nullable instance field '_textDecoration' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5154|10|11|Non-nullable instance field '_textIndent' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5166|10|14|Non-nullable instance field '_textTransform' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5178|10|4|Non-nullable instance field '_top' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5190|10|12|Non-nullable instance field '_unicodeBidi' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5202|10|14|Non-nullable instance field '_verticalAlign' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5214|10|11|Non-nullable instance field '_visibility' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5226|10|11|Non-nullable instance field '_whiteSpace' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5238|10|6|Non-nullable instance field '_width' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5250|10|12|Non-nullable instance field '_wordSpacing' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/html/dart2js/html_dart2js.dart|5262|10|7|Non-nullable instance field '_zIndex' must be initialized.
 ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/io/io.dart|5589|12|8|Non-nullable instance field 'encoding' must be initialized.
-ERROR|COMPILE_TIME_ERROR|NOT_INITIALIZED_NON_NULLABLE_INSTANCE_FIELD|lib/svg/dart2js/svg_dart2js.dart|4153|7|10|Non-nullable instance field 'zoomAndPan' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/html/dart2js/html_dart2js.dart|20081|13|7|The final variable 'keyCode' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/html/dart2js/html_dart2js.dart|20083|13|8|The final variable 'charCode' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/html/dart2js/html_dart2js.dart|21655|17|9|The final variable '_get_data' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/indexed_db/dart2js/indexed_db_dart2js.dart|1304|23|6|The final variable 'target' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/web_gl/dart2js/web_gl_dart2js.dart|89|23|6|The final variable 'canvas' must be initialized.
-ERROR|STATIC_WARNING|FINAL_NOT_INITIALIZED|lib/web_gl/dart2js/web_gl_dart2js.dart|92|25|15|The final variable 'offscreenCanvas' must be initialized.
 WARNING|STATIC_WARNING|DEAD_NULL_AWARE_EXPRESSION|lib/_http/http.dart|1476|39|5|The left operand can't be null, so the right operand is never executed.
 WARNING|STATIC_WARNING|DEAD_NULL_AWARE_EXPRESSION|lib/_http/http.dart|8384|60|5|The left operand can't be null, so the right operand is never executed.
 WARNING|STATIC_WARNING|DEAD_NULL_AWARE_EXPRESSION|lib/_http/http.dart|9311|54|5|The left operand can't be null, so the right operand is never executed.
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index 5e5e3b30f75..6d5f960de21 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -4067,7 +4067,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('background')
-  String _background;
+  String get _background native;
+
+  @JSName('background')
+  set _background(String value) native;
 
   /** Gets the value of "background-attachment" */
   String get backgroundAttachment => this._backgroundAttachment;
@@ -4079,7 +4082,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundAttachment')
-  String _backgroundAttachment;
+  String get _backgroundAttachment native;
+
+  @JSName('backgroundAttachment')
+  set _backgroundAttachment(String value) native;
 
   /** Gets the value of "background-color" */
   String get backgroundColor => this._backgroundColor;
@@ -4091,7 +4097,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundColor')
-  String _backgroundColor;
+  String get _backgroundColor native;
+
+  @JSName('backgroundColor')
+  set _backgroundColor(String value) native;
 
   /** Gets the value of "background-image" */
   String get backgroundImage => this._backgroundImage;
@@ -4103,7 +4112,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundImage')
-  String _backgroundImage;
+  String get _backgroundImage native;
+
+  @JSName('backgroundImage')
+  set _backgroundImage(String value) native;
 
   /** Gets the value of "background-position" */
   String get backgroundPosition => this._backgroundPosition;
@@ -4115,7 +4127,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundPosition')
-  String _backgroundPosition;
+  String get _backgroundPosition native;
+
+  @JSName('backgroundPosition')
+  set _backgroundPosition(String value) native;
 
   /** Gets the value of "background-repeat" */
   String get backgroundRepeat => this._backgroundRepeat;
@@ -4127,7 +4142,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundRepeat')
-  String _backgroundRepeat;
+  String get _backgroundRepeat native;
+
+  @JSName('backgroundRepeat')
+  set _backgroundRepeat(String value) native;
 
   /** Gets the value of "border" */
   String get border => this._border;
@@ -4139,7 +4157,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('border')
-  String _border;
+  String get _border native;
+
+  @JSName('border')
+  set _border(String value) native;
 
   /** Gets the value of "border-bottom" */
   String get borderBottom => this._borderBottom;
@@ -4151,7 +4172,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottom')
-  String _borderBottom;
+  String get _borderBottom native;
+
+  @JSName('borderBottom')
+  set _borderBottom(String value) native;
 
   /** Gets the value of "border-bottom-color" */
   String get borderBottomColor => this._borderBottomColor;
@@ -4163,7 +4187,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottomColor')
-  String _borderBottomColor;
+  String get _borderBottomColor native;
+
+  @JSName('borderBottomColor')
+  set _borderBottomColor(String value) native;
 
   /** Gets the value of "border-bottom-style" */
   String get borderBottomStyle => this._borderBottomStyle;
@@ -4175,7 +4202,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottomStyle')
-  String _borderBottomStyle;
+  String get _borderBottomStyle native;
+
+  @JSName('borderBottomStyle')
+  set _borderBottomStyle(String value) native;
 
   /** Gets the value of "border-bottom-width" */
   String get borderBottomWidth => this._borderBottomWidth;
@@ -4187,7 +4217,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottomWidth')
-  String _borderBottomWidth;
+  String get _borderBottomWidth native;
+
+  @JSName('borderBottomWidth')
+  set _borderBottomWidth(String value) native;
 
   /** Gets the value of "border-collapse" */
   String get borderCollapse => this._borderCollapse;
@@ -4199,7 +4232,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderCollapse')
-  String _borderCollapse;
+  String get _borderCollapse native;
+
+  @JSName('borderCollapse')
+  set _borderCollapse(String value) native;
 
   /** Gets the value of "border-color" */
   String get borderColor => this._borderColor;
@@ -4211,7 +4247,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderColor')
-  String _borderColor;
+  String get _borderColor native;
+
+  @JSName('borderColor')
+  set _borderColor(String value) native;
 
   /** Gets the value of "border-left" */
   String get borderLeft => this._borderLeft;
@@ -4223,7 +4262,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeft')
-  String _borderLeft;
+  String get _borderLeft native;
+
+  @JSName('borderLeft')
+  set _borderLeft(String value) native;
 
   /** Gets the value of "border-left-color" */
   String get borderLeftColor => this._borderLeftColor;
@@ -4235,7 +4277,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeftColor')
-  String _borderLeftColor;
+  String get _borderLeftColor native;
+
+  @JSName('borderLeftColor')
+  set _borderLeftColor(String value) native;
 
   /** Gets the value of "border-left-style" */
   String get borderLeftStyle => this._borderLeftStyle;
@@ -4247,7 +4292,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeftStyle')
-  String _borderLeftStyle;
+  String get _borderLeftStyle native;
+
+  @JSName('borderLeftStyle')
+  set _borderLeftStyle(String value) native;
 
   /** Gets the value of "border-left-width" */
   String get borderLeftWidth => this._borderLeftWidth;
@@ -4259,7 +4307,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeftWidth')
-  String _borderLeftWidth;
+  String get _borderLeftWidth native;
+
+  @JSName('borderLeftWidth')
+  set _borderLeftWidth(String value) native;
 
   /** Gets the value of "border-right" */
   String get borderRight => this._borderRight;
@@ -4271,7 +4322,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRight')
-  String _borderRight;
+  String get _borderRight native;
+
+  @JSName('borderRight')
+  set _borderRight(String value) native;
 
   /** Gets the value of "border-right-color" */
   String get borderRightColor => this._borderRightColor;
@@ -4283,7 +4337,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRightColor')
-  String _borderRightColor;
+  String get _borderRightColor native;
+
+  @JSName('borderRightColor')
+  set _borderRightColor(String value) native;
 
   /** Gets the value of "border-right-style" */
   String get borderRightStyle => this._borderRightStyle;
@@ -4295,7 +4352,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRightStyle')
-  String _borderRightStyle;
+  String get _borderRightStyle native;
+
+  @JSName('borderRightStyle')
+  set _borderRightStyle(String value) native;
 
   /** Gets the value of "border-right-width" */
   String get borderRightWidth => this._borderRightWidth;
@@ -4307,7 +4367,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRightWidth')
-  String _borderRightWidth;
+  String get _borderRightWidth native;
+
+  @JSName('borderRightWidth')
+  set _borderRightWidth(String value) native;
 
   /** Gets the value of "border-spacing" */
   String get borderSpacing => this._borderSpacing;
@@ -4319,7 +4382,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderSpacing')
-  String _borderSpacing;
+  String get _borderSpacing native;
+
+  @JSName('borderSpacing')
+  set _borderSpacing(String value) native;
 
   /** Gets the value of "border-style" */
   String get borderStyle => this._borderStyle;
@@ -4331,7 +4397,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderStyle')
-  String _borderStyle;
+  String get _borderStyle native;
+
+  @JSName('borderStyle')
+  set _borderStyle(String value) native;
 
   /** Gets the value of "border-top" */
   String get borderTop => this._borderTop;
@@ -4343,7 +4412,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTop')
-  String _borderTop;
+  String get _borderTop native;
+
+  @JSName('borderTop')
+  set _borderTop(String value) native;
 
   /** Gets the value of "border-top-color" */
   String get borderTopColor => this._borderTopColor;
@@ -4355,7 +4427,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTopColor')
-  String _borderTopColor;
+  String get _borderTopColor native;
+
+  @JSName('borderTopColor')
+  set _borderTopColor(String value) native;
 
   /** Gets the value of "border-top-style" */
   String get borderTopStyle => this._borderTopStyle;
@@ -4367,7 +4442,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTopStyle')
-  String _borderTopStyle;
+  String get _borderTopStyle native;
+
+  @JSName('borderTopStyle')
+  set _borderTopStyle(String value) native;
 
   /** Gets the value of "border-top-width" */
   String get borderTopWidth => this._borderTopWidth;
@@ -4379,7 +4457,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTopWidth')
-  String _borderTopWidth;
+  String get _borderTopWidth native;
+
+  @JSName('borderTopWidth')
+  set _borderTopWidth(String value) native;
 
   /** Gets the value of "border-width" */
   String get borderWidth => this._borderWidth;
@@ -4391,7 +4472,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderWidth')
-  String _borderWidth;
+  String get _borderWidth native;
+
+  @JSName('borderWidth')
+  set _borderWidth(String value) native;
 
   /** Gets the value of "bottom" */
   String get bottom => this._bottom;
@@ -4403,7 +4487,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('bottom')
-  String _bottom;
+  String get _bottom native;
+
+  @JSName('bottom')
+  set _bottom(String value) native;
 
   /** Gets the value of "caption-side" */
   String get captionSide => this._captionSide;
@@ -4415,7 +4502,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('captionSide')
-  String _captionSide;
+  String get _captionSide native;
+
+  @JSName('captionSide')
+  set _captionSide(String value) native;
 
   /** Gets the value of "clear" */
   String get clear => this._clear;
@@ -4427,7 +4517,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('clear')
-  String _clear;
+  String get _clear native;
+
+  @JSName('clear')
+  set _clear(String value) native;
 
   /** Gets the value of "clip" */
   String get clip => this._clip;
@@ -4439,7 +4532,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('clip')
-  String _clip;
+  String get _clip native;
+
+  @JSName('clip')
+  set _clip(String value) native;
 
   /** Gets the value of "color" */
   String get color => this._color;
@@ -4451,7 +4547,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('color')
-  String _color;
+  String get _color native;
+
+  @JSName('color')
+  set _color(String value) native;
 
   /** Gets the value of "content" */
   String get content => this._content;
@@ -4463,7 +4562,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('content')
-  String _content;
+  String get _content native;
+
+  @JSName('content')
+  set _content(String value) native;
 
   /** Gets the value of "cursor" */
   String get cursor => this._cursor;
@@ -4475,7 +4577,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('cursor')
-  String _cursor;
+  String get _cursor native;
+
+  @JSName('cursor')
+  set _cursor(String value) native;
 
   /** Gets the value of "direction" */
   String get direction => this._direction;
@@ -4487,7 +4592,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('direction')
-  String _direction;
+  String get _direction native;
+
+  @JSName('direction')
+  set _direction(String value) native;
 
   /** Gets the value of "display" */
   String get display => this._display;
@@ -4499,7 +4607,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('display')
-  String _display;
+  String get _display native;
+
+  @JSName('display')
+  set _display(String value) native;
 
   /** Gets the value of "empty-cells" */
   String get emptyCells => this._emptyCells;
@@ -4511,7 +4622,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('emptyCells')
-  String _emptyCells;
+  String get _emptyCells native;
+
+  @JSName('emptyCells')
+  set _emptyCells(String value) native;
 
   /** Gets the value of "font" */
   String get font => this._font;
@@ -4523,7 +4637,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('font')
-  String _font;
+  String get _font native;
+
+  @JSName('font')
+  set _font(String value) native;
 
   /** Gets the value of "font-family" */
   String get fontFamily => this._fontFamily;
@@ -4535,7 +4652,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontFamily')
-  String _fontFamily;
+  String get _fontFamily native;
+
+  @JSName('fontFamily')
+  set _fontFamily(String value) native;
 
   /** Gets the value of "font-size" */
   String get fontSize => this._fontSize;
@@ -4547,7 +4667,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontSize')
-  String _fontSize;
+  String get _fontSize native;
+
+  @JSName('fontSize')
+  set _fontSize(String value) native;
 
   /** Gets the value of "font-style" */
   String get fontStyle => this._fontStyle;
@@ -4559,7 +4682,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontStyle')
-  String _fontStyle;
+  String get _fontStyle native;
+
+  @JSName('fontStyle')
+  set _fontStyle(String value) native;
 
   /** Gets the value of "font-variant" */
   String get fontVariant => this._fontVariant;
@@ -4571,7 +4697,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontVariant')
-  String _fontVariant;
+  String get _fontVariant native;
+
+  @JSName('fontVariant')
+  set _fontVariant(String value) native;
 
   /** Gets the value of "font-weight" */
   String get fontWeight => this._fontWeight;
@@ -4583,7 +4712,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontWeight')
-  String _fontWeight;
+  String get _fontWeight native;
+
+  @JSName('fontWeight')
+  set _fontWeight(String value) native;
 
   /** Gets the value of "height" */
   String get height => this._height;
@@ -4595,7 +4727,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('height')
-  String _height;
+  String get _height native;
+
+  @JSName('height')
+  set _height(String value) native;
 
   /** Gets the value of "left" */
   String get left => this._left;
@@ -4607,7 +4742,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('left')
-  String _left;
+  String get _left native;
+
+  @JSName('left')
+  set _left(String value) native;
 
   /** Gets the value of "letter-spacing" */
   String get letterSpacing => this._letterSpacing;
@@ -4619,7 +4757,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('letterSpacing')
-  String _letterSpacing;
+  String get _letterSpacing native;
+
+  @JSName('letterSpacing')
+  set _letterSpacing(String value) native;
 
   /** Gets the value of "line-height" */
   String get lineHeight => this._lineHeight;
@@ -4631,7 +4772,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('lineHeight')
-  String _lineHeight;
+  String get _lineHeight native;
+
+  @JSName('lineHeight')
+  set _lineHeight(String value) native;
 
   /** Gets the value of "list-style" */
   String get listStyle => this._listStyle;
@@ -4643,7 +4787,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStyle')
-  String _listStyle;
+  String get _listStyle native;
+
+  @JSName('listStyle')
+  set _listStyle(String value) native;
 
   /** Gets the value of "list-style-image" */
   String get listStyleImage => this._listStyleImage;
@@ -4655,7 +4802,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStyleImage')
-  String _listStyleImage;
+  String get _listStyleImage native;
+
+  @JSName('listStyleImage')
+  set _listStyleImage(String value) native;
 
   /** Gets the value of "list-style-position" */
   String get listStylePosition => this._listStylePosition;
@@ -4667,7 +4817,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStylePosition')
-  String _listStylePosition;
+  String get _listStylePosition native;
+
+  @JSName('listStylePosition')
+  set _listStylePosition(String value) native;
 
   /** Gets the value of "list-style-type" */
   String get listStyleType => this._listStyleType;
@@ -4679,7 +4832,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStyleType')
-  String _listStyleType;
+  String get _listStyleType native;
+
+  @JSName('listStyleType')
+  set _listStyleType(String value) native;
 
   /** Gets the value of "margin" */
   String get margin => this._margin;
@@ -4691,7 +4847,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('margin')
-  String _margin;
+  String get _margin native;
+
+  @JSName('margin')
+  set _margin(String value) native;
 
   /** Gets the value of "margin-bottom" */
   String get marginBottom => this._marginBottom;
@@ -4703,7 +4862,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginBottom')
-  String _marginBottom;
+  String get _marginBottom native;
+
+  @JSName('marginBottom')
+  set _marginBottom(String value) native;
 
   /** Gets the value of "margin-left" */
   String get marginLeft => this._marginLeft;
@@ -4715,7 +4877,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginLeft')
-  String _marginLeft;
+  String get _marginLeft native;
+
+  @JSName('marginLeft')
+  set _marginLeft(String value) native;
 
   /** Gets the value of "margin-right" */
   String get marginRight => this._marginRight;
@@ -4727,7 +4892,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginRight')
-  String _marginRight;
+  String get _marginRight native;
+
+  @JSName('marginRight')
+  set _marginRight(String value) native;
 
   /** Gets the value of "margin-top" */
   String get marginTop => this._marginTop;
@@ -4739,7 +4907,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginTop')
-  String _marginTop;
+  String get _marginTop native;
+
+  @JSName('marginTop')
+  set _marginTop(String value) native;
 
   /** Gets the value of "max-height" */
   String get maxHeight => this._maxHeight;
@@ -4751,7 +4922,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('maxHeight')
-  String _maxHeight;
+  String get _maxHeight native;
+
+  @JSName('maxHeight')
+  set _maxHeight(String value) native;
 
   /** Gets the value of "max-width" */
   String get maxWidth => this._maxWidth;
@@ -4763,7 +4937,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('maxWidth')
-  String _maxWidth;
+  String get _maxWidth native;
+
+  @JSName('maxWidth')
+  set _maxWidth(String value) native;
 
   /** Gets the value of "min-height" */
   String get minHeight => this._minHeight;
@@ -4775,7 +4952,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('minHeight')
-  String _minHeight;
+  String get _minHeight native;
+
+  @JSName('minHeight')
+  set _minHeight(String value) native;
 
   /** Gets the value of "min-width" */
   String get minWidth => this._minWidth;
@@ -4787,7 +4967,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('minWidth')
-  String _minWidth;
+  String get _minWidth native;
+
+  @JSName('minWidth')
+  set _minWidth(String value) native;
 
   /** Gets the value of "outline" */
   String get outline => this._outline;
@@ -4799,7 +4982,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outline')
-  String _outline;
+  String get _outline native;
+
+  @JSName('outline')
+  set _outline(String value) native;
 
   /** Gets the value of "outline-color" */
   String get outlineColor => this._outlineColor;
@@ -4811,7 +4997,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outlineColor')
-  String _outlineColor;
+  String get _outlineColor native;
+
+  @JSName('outlineColor')
+  set _outlineColor(String value) native;
 
   /** Gets the value of "outline-style" */
   String get outlineStyle => this._outlineStyle;
@@ -4823,7 +5012,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outlineStyle')
-  String _outlineStyle;
+  String get _outlineStyle native;
+
+  @JSName('outlineStyle')
+  set _outlineStyle(String value) native;
 
   /** Gets the value of "outline-width" */
   String get outlineWidth => this._outlineWidth;
@@ -4835,7 +5027,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outlineWidth')
-  String _outlineWidth;
+  String get _outlineWidth native;
+
+  @JSName('outlineWidth')
+  set _outlineWidth(String value) native;
 
   /** Gets the value of "overflow" */
   String get overflow => this._overflow;
@@ -4847,7 +5042,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('overflow')
-  String _overflow;
+  String get _overflow native;
+
+  @JSName('overflow')
+  set _overflow(String value) native;
 
   /** Gets the value of "padding" */
   String get padding => this._padding;
@@ -4859,7 +5057,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('padding')
-  String _padding;
+  String get _padding native;
+
+  @JSName('padding')
+  set _padding(String value) native;
 
   /** Gets the value of "padding-bottom" */
   String get paddingBottom => this._paddingBottom;
@@ -4871,7 +5072,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingBottom')
-  String _paddingBottom;
+  String get _paddingBottom native;
+
+  @JSName('paddingBottom')
+  set _paddingBottom(String value) native;
 
   /** Gets the value of "padding-left" */
   String get paddingLeft => this._paddingLeft;
@@ -4883,7 +5087,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingLeft')
-  String _paddingLeft;
+  String get _paddingLeft native;
+
+  @JSName('paddingLeft')
+  set _paddingLeft(String value) native;
 
   /** Gets the value of "padding-right" */
   String get paddingRight => this._paddingRight;
@@ -4895,7 +5102,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingRight')
-  String _paddingRight;
+  String get _paddingRight native;
+
+  @JSName('paddingRight')
+  set _paddingRight(String value) native;
 
   /** Gets the value of "padding-top" */
   String get paddingTop => this._paddingTop;
@@ -4907,7 +5117,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingTop')
-  String _paddingTop;
+  String get _paddingTop native;
+
+  @JSName('paddingTop')
+  set _paddingTop(String value) native;
 
   /** Gets the value of "page-break-after" */
   String get pageBreakAfter => this._pageBreakAfter;
@@ -4919,7 +5132,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('pageBreakAfter')
-  String _pageBreakAfter;
+  String get _pageBreakAfter native;
+
+  @JSName('pageBreakAfter')
+  set _pageBreakAfter(String value) native;
 
   /** Gets the value of "page-break-before" */
   String get pageBreakBefore => this._pageBreakBefore;
@@ -4931,7 +5147,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('pageBreakBefore')
-  String _pageBreakBefore;
+  String get _pageBreakBefore native;
+
+  @JSName('pageBreakBefore')
+  set _pageBreakBefore(String value) native;
 
   /** Gets the value of "page-break-inside" */
   String get pageBreakInside => this._pageBreakInside;
@@ -4943,7 +5162,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('pageBreakInside')
-  String _pageBreakInside;
+  String get _pageBreakInside native;
+
+  @JSName('pageBreakInside')
+  set _pageBreakInside(String value) native;
 
   /** Gets the value of "position" */
   String get position => this._position;
@@ -4955,7 +5177,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('position')
-  String _position;
+  String get _position native;
+
+  @JSName('position')
+  set _position(String value) native;
 
   /** Gets the value of "quotes" */
   String get quotes => this._quotes;
@@ -4967,7 +5192,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('quotes')
-  String _quotes;
+  String get _quotes native;
+
+  @JSName('quotes')
+  set _quotes(String value) native;
 
   /** Gets the value of "right" */
   String get right => this._right;
@@ -4979,7 +5207,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('right')
-  String _right;
+  String get _right native;
+
+  @JSName('right')
+  set _right(String value) native;
 
   /** Gets the value of "table-layout" */
   String get tableLayout => this._tableLayout;
@@ -4991,7 +5222,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('tableLayout')
-  String _tableLayout;
+  String get _tableLayout native;
+
+  @JSName('tableLayout')
+  set _tableLayout(String value) native;
 
   /** Gets the value of "text-align" */
   String get textAlign => this._textAlign;
@@ -5003,7 +5237,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textAlign')
-  String _textAlign;
+  String get _textAlign native;
+
+  @JSName('textAlign')
+  set _textAlign(String value) native;
 
   /** Gets the value of "text-decoration" */
   String get textDecoration => this._textDecoration;
@@ -5015,7 +5252,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textDecoration')
-  String _textDecoration;
+  String get _textDecoration native;
+
+  @JSName('textDecoration')
+  set _textDecoration(String value) native;
 
   /** Gets the value of "text-indent" */
   String get textIndent => this._textIndent;
@@ -5027,7 +5267,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textIndent')
-  String _textIndent;
+  String get _textIndent native;
+
+  @JSName('textIndent')
+  set _textIndent(String value) native;
 
   /** Gets the value of "text-transform" */
   String get textTransform => this._textTransform;
@@ -5039,7 +5282,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textTransform')
-  String _textTransform;
+  String get _textTransform native;
+
+  @JSName('textTransform')
+  set _textTransform(String value) native;
 
   /** Gets the value of "top" */
   String get top => this._top;
@@ -5051,7 +5297,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('top')
-  String _top;
+  String get _top native;
+
+  @JSName('top')
+  set _top(String value) native;
 
   /** Gets the value of "unicode-bidi" */
   String get unicodeBidi => this._unicodeBidi;
@@ -5063,7 +5312,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('unicodeBidi')
-  String _unicodeBidi;
+  String get _unicodeBidi native;
+
+  @JSName('unicodeBidi')
+  set _unicodeBidi(String value) native;
 
   /** Gets the value of "vertical-align" */
   String get verticalAlign => this._verticalAlign;
@@ -5075,7 +5327,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('verticalAlign')
-  String _verticalAlign;
+  String get _verticalAlign native;
+
+  @JSName('verticalAlign')
+  set _verticalAlign(String value) native;
 
   /** Gets the value of "visibility" */
   String get visibility => this._visibility;
@@ -5087,7 +5342,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('visibility')
-  String _visibility;
+  String get _visibility native;
+
+  @JSName('visibility')
+  set _visibility(String value) native;
 
   /** Gets the value of "white-space" */
   String get whiteSpace => this._whiteSpace;
@@ -5099,7 +5357,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('whiteSpace')
-  String _whiteSpace;
+  String get _whiteSpace native;
+
+  @JSName('whiteSpace')
+  set _whiteSpace(String value) native;
 
   /** Gets the value of "width" */
   String get width => this._width;
@@ -5111,7 +5372,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('width')
-  String _width;
+  String get _width native;
+
+  @JSName('width')
+  set _width(String value) native;
 
   /** Gets the value of "word-spacing" */
   String get wordSpacing => this._wordSpacing;
@@ -5123,7 +5387,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('wordSpacing')
-  String _wordSpacing;
+  String get _wordSpacing native;
+
+  @JSName('wordSpacing')
+  set _wordSpacing(String value) native;
 
   /** Gets the value of "z-index" */
   String get zIndex => this._zIndex;
@@ -5135,7 +5402,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('zIndex')
-  String _zIndex;
+  String get _zIndex native;
+
+  @JSName('zIndex')
+  set _zIndex(String value) native;
 }
 
 class _CssStyleDeclarationSet extends Object with CssStyleDeclarationBase {
@@ -17310,7 +17580,8 @@ class HtmlDocument extends Document {
     throw new UnsupportedError("Not supported");
   }
 
-  BodyElement body;
+  BodyElement get body native;
+  set body(BodyElement value) native;
 
   /// UNSTABLE: Chrome-only - create a Range from the given point.
   @Unstable()
@@ -19017,7 +19288,8 @@ abstract class TextInputElementBase implements InputElementBase {
 abstract class SearchInputElement implements TextInputElementBase {
   factory SearchInputElement() => new InputElement(type: 'search');
 
-  String dirName;
+  String get dirName;
+  set dirName(String value);
 
   Element get list;
 
@@ -19033,7 +19305,8 @@ abstract class SearchInputElement implements TextInputElementBase {
 abstract class TextInputElement implements TextInputElementBase {
   factory TextInputElement() => new InputElement(type: 'text');
 
-  String dirName;
+  String get dirName;
+  set dirName(String value);
 
   Element get list;
 }
@@ -19093,25 +19366,34 @@ abstract class TelephoneInputElement implements TextInputElementBase {
 abstract class EmailInputElement implements TextInputElementBase {
   factory EmailInputElement() => new InputElement(type: 'email');
 
-  String autocomplete;
+  String get autocomplete;
+  set autocomplete(String value);
 
-  bool autofocus;
+  bool get autofocus;
+  set autofocus(bool value);
 
   Element get list;
 
-  int maxLength;
+  int get maxLength;
+  set maxLength(int value);
 
-  bool multiple;
+  bool get multiple;
+  set multiple(bool value);
 
-  String pattern;
+  String get pattern;
+  set pattern(String value);
 
-  String placeholder;
+  String get placeholder;
+  set placeholder(String value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
-  int size;
+  int get size;
+  set size(int value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19154,11 +19436,14 @@ abstract class RangeInputElementBase implements InputElementBase {
 abstract class DateInputElement implements RangeInputElementBase {
   factory DateInputElement() => new InputElement(type: 'date');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19175,11 +19460,14 @@ abstract class DateInputElement implements RangeInputElementBase {
 abstract class MonthInputElement implements RangeInputElementBase {
   factory MonthInputElement() => new InputElement(type: 'month');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19196,11 +19484,14 @@ abstract class MonthInputElement implements RangeInputElementBase {
 abstract class WeekInputElement implements RangeInputElementBase {
   factory WeekInputElement() => new InputElement(type: 'week');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19217,11 +19508,14 @@ abstract class WeekInputElement implements RangeInputElementBase {
 abstract class TimeInputElement implements RangeInputElementBase {
   factory TimeInputElement() => new InputElement(type: 'time');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19240,9 +19534,11 @@ abstract class LocalDateTimeInputElement implements RangeInputElementBase {
   factory LocalDateTimeInputElement() =>
       new InputElement(type: 'datetime-local');
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19259,11 +19555,14 @@ abstract class LocalDateTimeInputElement implements RangeInputElementBase {
 abstract class NumberInputElement implements RangeInputElementBase {
   factory NumberInputElement() => new InputElement(type: 'number');
 
-  String placeholder;
+  String get placeholder;
+  set placeholder(String value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19297,9 +19596,11 @@ abstract class RangeInputElement implements RangeInputElementBase {
 abstract class CheckboxInputElement implements InputElementBase {
   factory CheckboxInputElement() => new InputElement(type: 'checkbox');
 
-  bool checked;
+  bool get checked;
+  set checked(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 }
 
 /**
@@ -19316,9 +19617,11 @@ abstract class CheckboxInputElement implements InputElementBase {
 abstract class RadioButtonInputElement implements InputElementBase {
   factory RadioButtonInputElement() => new InputElement(type: 'radio');
 
-  bool checked;
+  bool get checked;
+  set checked(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 }
 
 /**
@@ -19327,11 +19630,14 @@ abstract class RadioButtonInputElement implements InputElementBase {
 abstract class FileUploadInputElement implements InputElementBase {
   factory FileUploadInputElement() => new InputElement(type: 'file');
 
-  String accept;
+  String get accept;
+  set accept(String value);
 
-  bool multiple;
+  bool get multiple;
+  set multiple(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   List<File> files;
 }
@@ -19342,15 +19648,20 @@ abstract class FileUploadInputElement implements InputElementBase {
 abstract class SubmitButtonInputElement implements InputElementBase {
   factory SubmitButtonInputElement() => new InputElement(type: 'submit');
 
-  String formAction;
+  String get formAction;
+  set formAction(String value);
 
-  String formEnctype;
+  String get formEnctype;
+  set formEnctype(String value);
 
-  String formMethod;
+  String get formMethod;
+  set formMethod(String value);
 
-  bool formNoValidate;
+  bool get formNoValidate;
+  set formNoValidate(bool value);
 
-  String formTarget;
+  String get formTarget;
+  set formTarget(String value);
 }
 
 /**
@@ -19360,23 +19671,32 @@ abstract class SubmitButtonInputElement implements InputElementBase {
 abstract class ImageButtonInputElement implements InputElementBase {
   factory ImageButtonInputElement() => new InputElement(type: 'image');
 
-  String alt;
+  String get alt;
+  set alt(String value);
 
-  String formAction;
+  String get formAction;
+  set formAction(String value);
 
-  String formEnctype;
+  String get formEnctype;
+  set formEnctype(String value);
 
-  String formMethod;
+  String get formMethod;
+  set formMethod(String value);
 
-  bool formNoValidate;
+  bool get formNoValidate;
+  set formNoValidate(bool value);
 
-  String formTarget;
+  String get formTarget;
+  set formTarget(String value);
 
-  int height;
+  int get height;
+  set height(int value);
 
-  String src;
+  String get src;
+  set src(String value);
 
-  int width;
+  int get width;
+  set width(int value);
 }
 
 /**
@@ -19599,9 +19919,9 @@ class KeyboardEvent extends UIEvent {
     }
   }
 
-  final int keyCode;
+  int get keyCode native;
 
-  final int charCode;
+  int get charCode native;
 
   int get which => _which;
 
@@ -21083,7 +21403,7 @@ class MessageEvent extends Event {
   @JSName('data')
   @annotation_Creates_SerializedScriptValue
   @annotation_Returns_SerializedScriptValue
-  final dynamic _get_data;
+  dynamic get _get_data native;
 
   factory MessageEvent._(String type, [Map eventInitDict]) {
     if (eventInitDict != null) {
diff --git a/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart b/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
index 141a4de1f7d..08bc19b06c4 100644
--- a/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
+++ b/sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart
@@ -1297,5 +1297,5 @@ class VersionChangeEvent extends Event {
   int get oldVersion native;
 
   @JSName('target')
-  final OpenDBRequest target;
+  OpenDBRequest get target native;
 }
diff --git a/sdk/lib/web_gl/dart2js/web_gl_dart2js.dart b/sdk/lib/web_gl/dart2js/web_gl_dart2js.dart
index db32a7d1b37..22d252cee3f 100644
--- a/sdk/lib/web_gl/dart2js/web_gl_dart2js.dart
+++ b/sdk/lib/web_gl/dart2js/web_gl_dart2js.dart
@@ -88,10 +88,10 @@ class Canvas extends Interceptor {
   }
 
   @JSName('canvas')
-  final CanvasElement canvas;
+  CanvasElement get canvas native;
 
   @JSName('canvas')
-  final OffscreenCanvas offscreenCanvas;
+  OffscreenCanvas get offscreenCanvas native;
 }
 
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
diff --git a/sdk_nnbd/lib/html/dart2js/html_dart2js.dart b/sdk_nnbd/lib/html/dart2js/html_dart2js.dart
index ed37110ab52..7d69d0ef1d9 100644
--- a/sdk_nnbd/lib/html/dart2js/html_dart2js.dart
+++ b/sdk_nnbd/lib/html/dart2js/html_dart2js.dart
@@ -4042,7 +4042,7 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
    * Checks to see if CSS Transitions are supported.
    */
   static bool get supportsTransitions {
-    return document.body.style.supportsProperty('transition');
+    return document.body!.style.supportsProperty('transition');
   }
 
   // To suppress missing implicit constructor warnings.
@@ -4081,7 +4081,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('background')
-  String _background;
+  String get _background native;
+
+  @JSName('background')
+  set _background(String value) native;
 
   /** Gets the value of "background-attachment" */
   String get backgroundAttachment => this._backgroundAttachment;
@@ -4093,7 +4096,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundAttachment')
-  String _backgroundAttachment;
+  String get _backgroundAttachment native;
+
+  @JSName('backgroundAttachment')
+  set _backgroundAttachment(String value) native;
 
   /** Gets the value of "background-color" */
   String get backgroundColor => this._backgroundColor;
@@ -4105,7 +4111,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundColor')
-  String _backgroundColor;
+  String get _backgroundColor native;
+
+  @JSName('backgroundColor')
+  set _backgroundColor(String value) native;
 
   /** Gets the value of "background-image" */
   String get backgroundImage => this._backgroundImage;
@@ -4117,7 +4126,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundImage')
-  String _backgroundImage;
+  String get _backgroundImage native;
+
+  @JSName('backgroundImage')
+  set _backgroundImage(String value) native;
 
   /** Gets the value of "background-position" */
   String get backgroundPosition => this._backgroundPosition;
@@ -4129,7 +4141,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundPosition')
-  String _backgroundPosition;
+  String get _backgroundPosition native;
+
+  @JSName('backgroundPosition')
+  set _backgroundPosition(String value) native;
 
   /** Gets the value of "background-repeat" */
   String get backgroundRepeat => this._backgroundRepeat;
@@ -4141,7 +4156,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('backgroundRepeat')
-  String _backgroundRepeat;
+  String get _backgroundRepeat native;
+
+  @JSName('backgroundRepeat')
+  set _backgroundRepeat(String value) native;
 
   /** Gets the value of "border" */
   String get border => this._border;
@@ -4153,7 +4171,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('border')
-  String _border;
+  String get _border native;
+
+  @JSName('border')
+  set _border(String value) native;
 
   /** Gets the value of "border-bottom" */
   String get borderBottom => this._borderBottom;
@@ -4165,7 +4186,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottom')
-  String _borderBottom;
+  String get _borderBottom native;
+
+  @JSName('borderBottom')
+  set _borderBottom(String value) native;
 
   /** Gets the value of "border-bottom-color" */
   String get borderBottomColor => this._borderBottomColor;
@@ -4177,7 +4201,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottomColor')
-  String _borderBottomColor;
+  String get _borderBottomColor native;
+
+  @JSName('borderBottomColor')
+  set _borderBottomColor(String value) native;
 
   /** Gets the value of "border-bottom-style" */
   String get borderBottomStyle => this._borderBottomStyle;
@@ -4189,7 +4216,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottomStyle')
-  String _borderBottomStyle;
+  String get _borderBottomStyle native;
+
+  @JSName('borderBottomStyle')
+  set _borderBottomStyle(String value) native;
 
   /** Gets the value of "border-bottom-width" */
   String get borderBottomWidth => this._borderBottomWidth;
@@ -4201,7 +4231,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderBottomWidth')
-  String _borderBottomWidth;
+  String get _borderBottomWidth native;
+
+  @JSName('borderBottomWidth')
+  set _borderBottomWidth(String value) native;
 
   /** Gets the value of "border-collapse" */
   String get borderCollapse => this._borderCollapse;
@@ -4213,7 +4246,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderCollapse')
-  String _borderCollapse;
+  String get _borderCollapse native;
+
+  @JSName('borderCollapse')
+  set _borderCollapse(String value) native;
 
   /** Gets the value of "border-color" */
   String get borderColor => this._borderColor;
@@ -4225,7 +4261,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderColor')
-  String _borderColor;
+  String get _borderColor native;
+
+  @JSName('borderColor')
+  set _borderColor(String value) native;
 
   /** Gets the value of "border-left" */
   String get borderLeft => this._borderLeft;
@@ -4237,7 +4276,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeft')
-  String _borderLeft;
+  String get _borderLeft native;
+
+  @JSName('borderLeft')
+  set _borderLeft(String value) native;
 
   /** Gets the value of "border-left-color" */
   String get borderLeftColor => this._borderLeftColor;
@@ -4249,7 +4291,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeftColor')
-  String _borderLeftColor;
+  String get _borderLeftColor native;
+
+  @JSName('borderLeftColor')
+  set _borderLeftColor(String value) native;
 
   /** Gets the value of "border-left-style" */
   String get borderLeftStyle => this._borderLeftStyle;
@@ -4261,7 +4306,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeftStyle')
-  String _borderLeftStyle;
+  String get _borderLeftStyle native;
+
+  @JSName('borderLeftStyle')
+  set _borderLeftStyle(String value) native;
 
   /** Gets the value of "border-left-width" */
   String get borderLeftWidth => this._borderLeftWidth;
@@ -4273,7 +4321,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderLeftWidth')
-  String _borderLeftWidth;
+  String get _borderLeftWidth native;
+
+  @JSName('borderLeftWidth')
+  set _borderLeftWidth(String value) native;
 
   /** Gets the value of "border-right" */
   String get borderRight => this._borderRight;
@@ -4285,7 +4336,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRight')
-  String _borderRight;
+  String get _borderRight native;
+
+  @JSName('borderRight')
+  set _borderRight(String value) native;
 
   /** Gets the value of "border-right-color" */
   String get borderRightColor => this._borderRightColor;
@@ -4297,7 +4351,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRightColor')
-  String _borderRightColor;
+  String get _borderRightColor native;
+
+  @JSName('borderRightColor')
+  set _borderRightColor(String value) native;
 
   /** Gets the value of "border-right-style" */
   String get borderRightStyle => this._borderRightStyle;
@@ -4309,7 +4366,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRightStyle')
-  String _borderRightStyle;
+  String get _borderRightStyle native;
+
+  @JSName('borderRightStyle')
+  set _borderRightStyle(String value) native;
 
   /** Gets the value of "border-right-width" */
   String get borderRightWidth => this._borderRightWidth;
@@ -4321,7 +4381,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderRightWidth')
-  String _borderRightWidth;
+  String get _borderRightWidth native;
+
+  @JSName('borderRightWidth')
+  set _borderRightWidth(String value) native;
 
   /** Gets the value of "border-spacing" */
   String get borderSpacing => this._borderSpacing;
@@ -4333,7 +4396,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderSpacing')
-  String _borderSpacing;
+  String get _borderSpacing native;
+
+  @JSName('borderSpacing')
+  set _borderSpacing(String value) native;
 
   /** Gets the value of "border-style" */
   String get borderStyle => this._borderStyle;
@@ -4345,7 +4411,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderStyle')
-  String _borderStyle;
+  String get _borderStyle native;
+
+  @JSName('borderStyle')
+  set _borderStyle(String value) native;
 
   /** Gets the value of "border-top" */
   String get borderTop => this._borderTop;
@@ -4357,7 +4426,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTop')
-  String _borderTop;
+  String get _borderTop native;
+
+  @JSName('borderTop')
+  set _borderTop(String value) native;
 
   /** Gets the value of "border-top-color" */
   String get borderTopColor => this._borderTopColor;
@@ -4369,7 +4441,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTopColor')
-  String _borderTopColor;
+  String get _borderTopColor native;
+
+  @JSName('borderTopColor')
+  set _borderTopColor(String value) native;
 
   /** Gets the value of "border-top-style" */
   String get borderTopStyle => this._borderTopStyle;
@@ -4381,7 +4456,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTopStyle')
-  String _borderTopStyle;
+  String get _borderTopStyle native;
+
+  @JSName('borderTopStyle')
+  set _borderTopStyle(String value) native;
 
   /** Gets the value of "border-top-width" */
   String get borderTopWidth => this._borderTopWidth;
@@ -4393,7 +4471,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderTopWidth')
-  String _borderTopWidth;
+  String get _borderTopWidth native;
+
+  @JSName('borderTopWidth')
+  set _borderTopWidth(String value) native;
 
   /** Gets the value of "border-width" */
   String get borderWidth => this._borderWidth;
@@ -4405,7 +4486,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('borderWidth')
-  String _borderWidth;
+  String get _borderWidth native;
+
+  @JSName('borderWidth')
+  set _borderWidth(String value) native;
 
   /** Gets the value of "bottom" */
   String get bottom => this._bottom;
@@ -4417,7 +4501,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('bottom')
-  String _bottom;
+  String get _bottom native;
+
+  @JSName('bottom')
+  set _bottom(String value) native;
 
   /** Gets the value of "caption-side" */
   String get captionSide => this._captionSide;
@@ -4429,7 +4516,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('captionSide')
-  String _captionSide;
+  String get _captionSide native;
+
+  @JSName('captionSide')
+  set _captionSide(String value) native;
 
   /** Gets the value of "clear" */
   String get clear => this._clear;
@@ -4441,7 +4531,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('clear')
-  String _clear;
+  String get _clear native;
+
+  @JSName('clear')
+  set _clear(String value) native;
 
   /** Gets the value of "clip" */
   String get clip => this._clip;
@@ -4453,7 +4546,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('clip')
-  String _clip;
+  String get _clip native;
+
+  @JSName('clip')
+  set _clip(String value) native;
 
   /** Gets the value of "color" */
   String get color => this._color;
@@ -4465,7 +4561,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('color')
-  String _color;
+  String get _color native;
+
+  @JSName('color')
+  set _color(String value) native;
 
   /** Gets the value of "content" */
   String get content => this._content;
@@ -4477,7 +4576,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('content')
-  String _content;
+  String get _content native;
+
+  @JSName('content')
+  set _content(String value) native;
 
   /** Gets the value of "cursor" */
   String get cursor => this._cursor;
@@ -4489,7 +4591,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('cursor')
-  String _cursor;
+  String get _cursor native;
+
+  @JSName('cursor')
+  set _cursor(String value) native;
 
   /** Gets the value of "direction" */
   String get direction => this._direction;
@@ -4501,7 +4606,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('direction')
-  String _direction;
+  String get _direction native;
+
+  @JSName('direction')
+  set _direction(String value) native;
 
   /** Gets the value of "display" */
   String get display => this._display;
@@ -4513,7 +4621,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('display')
-  String _display;
+  String get _display native;
+
+  @JSName('display')
+  set _display(String value) native;
 
   /** Gets the value of "empty-cells" */
   String get emptyCells => this._emptyCells;
@@ -4525,7 +4636,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('emptyCells')
-  String _emptyCells;
+  String get _emptyCells native;
+
+  @JSName('emptyCells')
+  set _emptyCells(String value) native;
 
   /** Gets the value of "font" */
   String get font => this._font;
@@ -4537,7 +4651,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('font')
-  String _font;
+  String get _font native;
+
+  @JSName('font')
+  set _font(String value) native;
 
   /** Gets the value of "font-family" */
   String get fontFamily => this._fontFamily;
@@ -4549,7 +4666,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontFamily')
-  String _fontFamily;
+  String get _fontFamily native;
+
+  @JSName('fontFamily')
+  set _fontFamily(String value) native;
 
   /** Gets the value of "font-size" */
   String get fontSize => this._fontSize;
@@ -4561,7 +4681,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontSize')
-  String _fontSize;
+  String get _fontSize native;
+
+  @JSName('fontSize')
+  set _fontSize(String value) native;
 
   /** Gets the value of "font-style" */
   String get fontStyle => this._fontStyle;
@@ -4573,7 +4696,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontStyle')
-  String _fontStyle;
+  String get _fontStyle native;
+
+  @JSName('fontStyle')
+  set _fontStyle(String value) native;
 
   /** Gets the value of "font-variant" */
   String get fontVariant => this._fontVariant;
@@ -4585,7 +4711,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontVariant')
-  String _fontVariant;
+  String get _fontVariant native;
+
+  @JSName('fontVariant')
+  set _fontVariant(String value) native;
 
   /** Gets the value of "font-weight" */
   String get fontWeight => this._fontWeight;
@@ -4597,7 +4726,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('fontWeight')
-  String _fontWeight;
+  String get _fontWeight native;
+
+  @JSName('fontWeight')
+  set _fontWeight(String value) native;
 
   /** Gets the value of "height" */
   String get height => this._height;
@@ -4609,7 +4741,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('height')
-  String _height;
+  String get _height native;
+
+  @JSName('height')
+  set _height(String value) native;
 
   /** Gets the value of "left" */
   String get left => this._left;
@@ -4621,7 +4756,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('left')
-  String _left;
+  String get _left native;
+
+  @JSName('left')
+  set _left(String value) native;
 
   /** Gets the value of "letter-spacing" */
   String get letterSpacing => this._letterSpacing;
@@ -4633,7 +4771,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('letterSpacing')
-  String _letterSpacing;
+  String get _letterSpacing native;
+
+  @JSName('letterSpacing')
+  set _letterSpacing(String value) native;
 
   /** Gets the value of "line-height" */
   String get lineHeight => this._lineHeight;
@@ -4645,7 +4786,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('lineHeight')
-  String _lineHeight;
+  String get _lineHeight native;
+
+  @JSName('lineHeight')
+  set _lineHeight(String value) native;
 
   /** Gets the value of "list-style" */
   String get listStyle => this._listStyle;
@@ -4657,7 +4801,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStyle')
-  String _listStyle;
+  String get _listStyle native;
+
+  @JSName('listStyle')
+  set _listStyle(String value) native;
 
   /** Gets the value of "list-style-image" */
   String get listStyleImage => this._listStyleImage;
@@ -4669,7 +4816,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStyleImage')
-  String _listStyleImage;
+  String get _listStyleImage native;
+
+  @JSName('listStyleImage')
+  set _listStyleImage(String value) native;
 
   /** Gets the value of "list-style-position" */
   String get listStylePosition => this._listStylePosition;
@@ -4681,7 +4831,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStylePosition')
-  String _listStylePosition;
+  String get _listStylePosition native;
+
+  @JSName('listStylePosition')
+  set _listStylePosition(String value) native;
 
   /** Gets the value of "list-style-type" */
   String get listStyleType => this._listStyleType;
@@ -4693,7 +4846,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('listStyleType')
-  String _listStyleType;
+  String get _listStyleType native;
+
+  @JSName('listStyleType')
+  set _listStyleType(String value) native;
 
   /** Gets the value of "margin" */
   String get margin => this._margin;
@@ -4705,7 +4861,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('margin')
-  String _margin;
+  String get _margin native;
+
+  @JSName('margin')
+  set _margin(String value) native;
 
   /** Gets the value of "margin-bottom" */
   String get marginBottom => this._marginBottom;
@@ -4717,7 +4876,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginBottom')
-  String _marginBottom;
+  String get _marginBottom native;
+
+  @JSName('marginBottom')
+  set _marginBottom(String value) native;
 
   /** Gets the value of "margin-left" */
   String get marginLeft => this._marginLeft;
@@ -4729,7 +4891,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginLeft')
-  String _marginLeft;
+  String get _marginLeft native;
+
+  @JSName('marginLeft')
+  set _marginLeft(String value) native;
 
   /** Gets the value of "margin-right" */
   String get marginRight => this._marginRight;
@@ -4741,7 +4906,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginRight')
-  String _marginRight;
+  String get _marginRight native;
+
+  @JSName('marginRight')
+  set _marginRight(String value) native;
 
   /** Gets the value of "margin-top" */
   String get marginTop => this._marginTop;
@@ -4753,7 +4921,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('marginTop')
-  String _marginTop;
+  String get _marginTop native;
+
+  @JSName('marginTop')
+  set _marginTop(String value) native;
 
   /** Gets the value of "max-height" */
   String get maxHeight => this._maxHeight;
@@ -4765,7 +4936,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('maxHeight')
-  String _maxHeight;
+  String get _maxHeight native;
+
+  @JSName('maxHeight')
+  set _maxHeight(String value) native;
 
   /** Gets the value of "max-width" */
   String get maxWidth => this._maxWidth;
@@ -4777,7 +4951,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('maxWidth')
-  String _maxWidth;
+  String get _maxWidth native;
+
+  @JSName('maxWidth')
+  set _maxWidth(String value) native;
 
   /** Gets the value of "min-height" */
   String get minHeight => this._minHeight;
@@ -4789,7 +4966,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('minHeight')
-  String _minHeight;
+  String get _minHeight native;
+
+  @JSName('minHeight')
+  set _minHeight(String value) native;
 
   /** Gets the value of "min-width" */
   String get minWidth => this._minWidth;
@@ -4801,7 +4981,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('minWidth')
-  String _minWidth;
+  String get _minWidth native;
+
+  @JSName('minWidth')
+  set _minWidth(String value) native;
 
   /** Gets the value of "outline" */
   String get outline => this._outline;
@@ -4813,7 +4996,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outline')
-  String _outline;
+  String get _outline native;
+
+  @JSName('outline')
+  set _outline(String value) native;
 
   /** Gets the value of "outline-color" */
   String get outlineColor => this._outlineColor;
@@ -4825,7 +5011,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outlineColor')
-  String _outlineColor;
+  String get _outlineColor native;
+
+  @JSName('outlineColor')
+  set _outlineColor(String value) native;
 
   /** Gets the value of "outline-style" */
   String get outlineStyle => this._outlineStyle;
@@ -4837,7 +5026,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outlineStyle')
-  String _outlineStyle;
+  String get _outlineStyle native;
+
+  @JSName('outlineStyle')
+  set _outlineStyle(String value) native;
 
   /** Gets the value of "outline-width" */
   String get outlineWidth => this._outlineWidth;
@@ -4849,7 +5041,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('outlineWidth')
-  String _outlineWidth;
+  String get _outlineWidth native;
+
+  @JSName('outlineWidth')
+  set _outlineWidth(String value) native;
 
   /** Gets the value of "overflow" */
   String get overflow => this._overflow;
@@ -4861,7 +5056,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('overflow')
-  String _overflow;
+  String get _overflow native;
+
+  @JSName('overflow')
+  set _overflow(String value) native;
 
   /** Gets the value of "padding" */
   String get padding => this._padding;
@@ -4873,7 +5071,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('padding')
-  String _padding;
+  String get _padding native;
+
+  @JSName('padding')
+  set _padding(String value) native;
 
   /** Gets the value of "padding-bottom" */
   String get paddingBottom => this._paddingBottom;
@@ -4885,7 +5086,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingBottom')
-  String _paddingBottom;
+  String get _paddingBottom native;
+
+  @JSName('paddingBottom')
+  set _paddingBottom(String value) native;
 
   /** Gets the value of "padding-left" */
   String get paddingLeft => this._paddingLeft;
@@ -4897,7 +5101,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingLeft')
-  String _paddingLeft;
+  String get _paddingLeft native;
+
+  @JSName('paddingLeft')
+  set _paddingLeft(String value) native;
 
   /** Gets the value of "padding-right" */
   String get paddingRight => this._paddingRight;
@@ -4909,7 +5116,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingRight')
-  String _paddingRight;
+  String get _paddingRight native;
+
+  @JSName('paddingRight')
+  set _paddingRight(String value) native;
 
   /** Gets the value of "padding-top" */
   String get paddingTop => this._paddingTop;
@@ -4921,7 +5131,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('paddingTop')
-  String _paddingTop;
+  String get _paddingTop native;
+
+  @JSName('paddingTop')
+  set _paddingTop(String value) native;
 
   /** Gets the value of "page-break-after" */
   String get pageBreakAfter => this._pageBreakAfter;
@@ -4933,7 +5146,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('pageBreakAfter')
-  String _pageBreakAfter;
+  String get _pageBreakAfter native;
+
+  @JSName('pageBreakAfter')
+  set _pageBreakAfter(String value) native;
 
   /** Gets the value of "page-break-before" */
   String get pageBreakBefore => this._pageBreakBefore;
@@ -4945,7 +5161,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('pageBreakBefore')
-  String _pageBreakBefore;
+  String get _pageBreakBefore native;
+
+  @JSName('pageBreakBefore')
+  set _pageBreakBefore(String value) native;
 
   /** Gets the value of "page-break-inside" */
   String get pageBreakInside => this._pageBreakInside;
@@ -4957,7 +5176,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('pageBreakInside')
-  String _pageBreakInside;
+  String get _pageBreakInside native;
+
+  @JSName('pageBreakInside')
+  set _pageBreakInside(String value) native;
 
   /** Gets the value of "position" */
   String get position => this._position;
@@ -4969,7 +5191,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('position')
-  String _position;
+  String get _position native;
+
+  @JSName('position')
+  set _position(String value) native;
 
   /** Gets the value of "quotes" */
   String get quotes => this._quotes;
@@ -4981,7 +5206,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('quotes')
-  String _quotes;
+  String get _quotes native;
+
+  @JSName('quotes')
+  set _quotes(String value) native;
 
   /** Gets the value of "right" */
   String get right => this._right;
@@ -4993,7 +5221,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('right')
-  String _right;
+  String get _right native;
+
+  @JSName('right')
+  set _right(String value) native;
 
   /** Gets the value of "table-layout" */
   String get tableLayout => this._tableLayout;
@@ -5005,7 +5236,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('tableLayout')
-  String _tableLayout;
+  String get _tableLayout native;
+
+  @JSName('tableLayout')
+  set _tableLayout(String value) native;
 
   /** Gets the value of "text-align" */
   String get textAlign => this._textAlign;
@@ -5017,7 +5251,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textAlign')
-  String _textAlign;
+  String get _textAlign native;
+
+  @JSName('textAlign')
+  set _textAlign(String value) native;
 
   /** Gets the value of "text-decoration" */
   String get textDecoration => this._textDecoration;
@@ -5029,7 +5266,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textDecoration')
-  String _textDecoration;
+  String get _textDecoration native;
+
+  @JSName('textDecoration')
+  set _textDecoration(String value) native;
 
   /** Gets the value of "text-indent" */
   String get textIndent => this._textIndent;
@@ -5041,7 +5281,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textIndent')
-  String _textIndent;
+  String get _textIndent native;
+
+  @JSName('textIndent')
+  set _textIndent(String value) native;
 
   /** Gets the value of "text-transform" */
   String get textTransform => this._textTransform;
@@ -5053,7 +5296,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('textTransform')
-  String _textTransform;
+  String get _textTransform native;
+
+  @JSName('textTransform')
+  set _textTransform(String value) native;
 
   /** Gets the value of "top" */
   String get top => this._top;
@@ -5065,7 +5311,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('top')
-  String _top;
+  String get _top native;
+
+  @JSName('top')
+  set _top(String value) native;
 
   /** Gets the value of "unicode-bidi" */
   String get unicodeBidi => this._unicodeBidi;
@@ -5077,7 +5326,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('unicodeBidi')
-  String _unicodeBidi;
+  String get _unicodeBidi native;
+
+  @JSName('unicodeBidi')
+  set _unicodeBidi(String value) native;
 
   /** Gets the value of "vertical-align" */
   String get verticalAlign => this._verticalAlign;
@@ -5089,7 +5341,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('verticalAlign')
-  String _verticalAlign;
+  String get _verticalAlign native;
+
+  @JSName('verticalAlign')
+  set _verticalAlign(String value) native;
 
   /** Gets the value of "visibility" */
   String get visibility => this._visibility;
@@ -5101,7 +5356,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('visibility')
-  String _visibility;
+  String get _visibility native;
+
+  @JSName('visibility')
+  set _visibility(String value) native;
 
   /** Gets the value of "white-space" */
   String get whiteSpace => this._whiteSpace;
@@ -5113,7 +5371,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('whiteSpace')
-  String _whiteSpace;
+  String get _whiteSpace native;
+
+  @JSName('whiteSpace')
+  set _whiteSpace(String value) native;
 
   /** Gets the value of "width" */
   String get width => this._width;
@@ -5125,7 +5386,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('width')
-  String _width;
+  String get _width native;
+
+  @JSName('width')
+  set _width(String value) native;
 
   /** Gets the value of "word-spacing" */
   String get wordSpacing => this._wordSpacing;
@@ -5137,7 +5401,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('wordSpacing')
-  String _wordSpacing;
+  String get _wordSpacing native;
+
+  @JSName('wordSpacing')
+  set _wordSpacing(String value) native;
 
   /** Gets the value of "z-index" */
   String get zIndex => this._zIndex;
@@ -5149,7 +5416,10 @@ class CssStyleDeclaration extends Interceptor with CssStyleDeclarationBase {
 
   @Returns('String')
   @JSName('zIndex')
-  String _zIndex;
+  String get _zIndex native;
+
+  @JSName('zIndex')
+  set _zIndex(String value) native;
 }
 
 class _CssStyleDeclarationSet extends Object with CssStyleDeclarationBase {
@@ -10183,7 +10453,7 @@ class DocumentFragment extends Node
 
   factory DocumentFragment.html(String html,
       {NodeValidator? validator, NodeTreeSanitizer? treeSanitizer}) {
-    return document.body.createFragment(html,
+    return document.body!.createFragment(html,
         validator: validator, treeSanitizer: treeSanitizer);
   }
 
@@ -10243,7 +10513,7 @@ class DocumentFragment extends Node
   void setInnerHtml(String html,
       {NodeValidator? validator, NodeTreeSanitizer? treeSanitizer}) {
     this.nodes.clear();
-    append(document.body.createFragment(html,
+    append(document.body!.createFragment(html,
         validator: validator, treeSanitizer: treeSanitizer));
   }
 
@@ -12396,7 +12666,7 @@ class Element extends Node
    */
   factory Element.html(String html,
       {NodeValidator? validator, NodeTreeSanitizer? treeSanitizer}) {
-    var fragment = document.body.createFragment(html,
+    var fragment = document.body!.createFragment(html,
         validator: validator, treeSanitizer: treeSanitizer);
 
     return fragment.nodes.where((e) => e is Element).single as Element;
@@ -13387,10 +13657,10 @@ class Element extends Node
 
     var contextElement;
     if (this is BodyElement) {
-      contextElement = _parseDocument!.body;
+      contextElement = _parseDocument!.body!;
     } else {
       contextElement = _parseDocument!.createElement(tagName);
-      _parseDocument!.body.append(contextElement);
+      _parseDocument!.body!.append(contextElement);
     }
     var fragment;
     if (Range.supportsCreateContextualFragment &&
@@ -17338,7 +17608,8 @@ class HtmlDocument extends Document {
     throw new UnsupportedError("Not supported");
   }
 
-  BodyElement body;
+  BodyElement? get body native;
+  set body(BodyElement? value) native;
 
   /// UNSTABLE: Chrome-only - create a Range from the given point.
   @Unstable()
@@ -19063,7 +19334,8 @@ abstract class TextInputElementBase implements InputElementBase {
 abstract class SearchInputElement implements TextInputElementBase {
   factory SearchInputElement() => new InputElement(type: 'search');
 
-  String dirName;
+  String get dirName;
+  set dirName(String value);
 
   Element? get list;
 
@@ -19079,7 +19351,8 @@ abstract class SearchInputElement implements TextInputElementBase {
 abstract class TextInputElement implements TextInputElementBase {
   factory TextInputElement() => new InputElement(type: 'text');
 
-  String dirName;
+  String get dirName;
+  set dirName(String value);
 
   Element? get list;
 }
@@ -19139,25 +19412,34 @@ abstract class TelephoneInputElement implements TextInputElementBase {
 abstract class EmailInputElement implements TextInputElementBase {
   factory EmailInputElement() => new InputElement(type: 'email');
 
-  String autocomplete;
+  String get autocomplete;
+  set autocomplete(String value);
 
-  bool autofocus;
+  bool get autofocus;
+  set autofocus(bool value);
 
   Element? get list;
 
-  int maxLength;
+  int get maxLength;
+  set maxLength(int value);
 
-  bool multiple;
+  bool get multiple;
+  set multiple(bool value);
 
-  String pattern;
+  String get pattern;
+  set pattern(String value);
 
-  String placeholder;
+  String get placeholder;
+  set placeholder(String value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
-  int size;
+  int get size;
+  set size(int value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19204,11 +19486,14 @@ abstract class RangeInputElementBase implements InputElementBase {
 abstract class DateInputElement implements RangeInputElementBase {
   factory DateInputElement() => new InputElement(type: 'date');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19225,11 +19510,14 @@ abstract class DateInputElement implements RangeInputElementBase {
 abstract class MonthInputElement implements RangeInputElementBase {
   factory MonthInputElement() => new InputElement(type: 'month');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19246,11 +19534,14 @@ abstract class MonthInputElement implements RangeInputElementBase {
 abstract class WeekInputElement implements RangeInputElementBase {
   factory WeekInputElement() => new InputElement(type: 'week');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19267,11 +19558,14 @@ abstract class WeekInputElement implements RangeInputElementBase {
 abstract class TimeInputElement implements RangeInputElementBase {
   factory TimeInputElement() => new InputElement(type: 'time');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19290,9 +19584,11 @@ abstract class LocalDateTimeInputElement implements RangeInputElementBase {
   factory LocalDateTimeInputElement() =>
       new InputElement(type: 'datetime-local');
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19309,11 +19605,14 @@ abstract class LocalDateTimeInputElement implements RangeInputElementBase {
 abstract class NumberInputElement implements RangeInputElementBase {
   factory NumberInputElement() => new InputElement(type: 'number');
 
-  String placeholder;
+  String get placeholder;
+  set placeholder(String value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -19347,9 +19646,11 @@ abstract class RangeInputElement implements RangeInputElementBase {
 abstract class CheckboxInputElement implements InputElementBase {
   factory CheckboxInputElement() => new InputElement(type: 'checkbox');
 
-  bool checked;
+  bool get checked;
+  set checked(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 }
 
 /**
@@ -19366,9 +19667,11 @@ abstract class CheckboxInputElement implements InputElementBase {
 abstract class RadioButtonInputElement implements InputElementBase {
   factory RadioButtonInputElement() => new InputElement(type: 'radio');
 
-  bool checked;
+  bool get checked;
+  set checked(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 }
 
 /**
@@ -19377,11 +19680,14 @@ abstract class RadioButtonInputElement implements InputElementBase {
 abstract class FileUploadInputElement implements InputElementBase {
   factory FileUploadInputElement() => new InputElement(type: 'file');
 
-  String accept;
+  String get accept;
+  set accept(String value);
 
-  bool multiple;
+  bool get multiple;
+  set multiple(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   List<File>? files;
 }
@@ -19392,15 +19698,20 @@ abstract class FileUploadInputElement implements InputElementBase {
 abstract class SubmitButtonInputElement implements InputElementBase {
   factory SubmitButtonInputElement() => new InputElement(type: 'submit');
 
-  String formAction;
+  String get formAction;
+  set formAction(String value);
 
-  String formEnctype;
+  String get formEnctype;
+  set formEnctype(String value);
 
-  String formMethod;
+  String get formMethod;
+  set formMethod(String value);
 
-  bool formNoValidate;
+  bool get formNoValidate;
+  set formNoValidate(bool value);
 
-  String formTarget;
+  String get formTarget;
+  set formTarget(String value);
 }
 
 /**
@@ -19410,23 +19721,32 @@ abstract class SubmitButtonInputElement implements InputElementBase {
 abstract class ImageButtonInputElement implements InputElementBase {
   factory ImageButtonInputElement() => new InputElement(type: 'image');
 
-  String alt;
+  String get alt;
+  set alt(String value);
 
-  String formAction;
+  String get formAction;
+  set formAction(String value);
 
-  String formEnctype;
+  String get formEnctype;
+  set formEnctype(String value);
 
-  String formMethod;
+  String get formMethod;
+  set formMethod(String value);
 
-  bool formNoValidate;
+  bool get formNoValidate;
+  set formNoValidate(bool value);
 
-  String formTarget;
+  String get formTarget;
+  set formTarget(String value);
 
-  int height;
+  int get height;
+  set height(int value);
 
-  String src;
+  String get src;
+  set src(String value);
 
-  int width;
+  int get width;
+  set width(int value);
 }
 
 /**
@@ -19649,9 +19969,9 @@ class KeyboardEvent extends UIEvent {
     }
   }
 
-  final int keyCode;
+  int get keyCode native;
 
-  final int charCode;
+  int get charCode native;
 
   int get which => _which;
 
@@ -21139,7 +21459,7 @@ class MessageEvent extends Event {
   @JSName('data')
   @annotation_Creates_SerializedScriptValue
   @annotation_Returns_SerializedScriptValue
-  final dynamic _get_data;
+  dynamic get _get_data native;
 
   factory MessageEvent._(String type, [Map? eventInitDict]) {
     if (eventInitDict != null) {
diff --git a/sdk_nnbd/lib/indexed_db/dart2js/indexed_db_dart2js.dart b/sdk_nnbd/lib/indexed_db/dart2js/indexed_db_dart2js.dart
index 3f0f9f86e3e..4bbd020da37 100644
--- a/sdk_nnbd/lib/indexed_db/dart2js/indexed_db_dart2js.dart
+++ b/sdk_nnbd/lib/indexed_db/dart2js/indexed_db_dart2js.dart
@@ -1295,5 +1295,5 @@ class VersionChangeEvent extends Event {
   int get oldVersion native;
 
   @JSName('target')
-  final OpenDBRequest target;
+  OpenDBRequest get target native;
 }
diff --git a/sdk_nnbd/lib/svg/dart2js/svg_dart2js.dart b/sdk_nnbd/lib/svg/dart2js/svg_dart2js.dart
index 0a4bd44eed6..8eaabef0b20 100644
--- a/sdk_nnbd/lib/svg/dart2js/svg_dart2js.dart
+++ b/sdk_nnbd/lib/svg/dart2js/svg_dart2js.dart
@@ -3053,7 +3053,7 @@ class SvgElement extends Element implements GlobalEventHandlers, NoncedElement {
     // We create a fragment which will parse in the HTML parser
     var html = '<svg version="1.1">$svg</svg>';
     var fragment =
-        document.body.createFragment(html, treeSanitizer: treeSanitizer);
+        document.body!.createFragment(html, treeSanitizer: treeSanitizer);
 
     var svgFragment = new DocumentFragment();
     // The root is the <svg/> element, need to pull out the contents.
diff --git a/sdk_nnbd/lib/web_gl/dart2js/web_gl_dart2js.dart b/sdk_nnbd/lib/web_gl/dart2js/web_gl_dart2js.dart
index 6c3e7d708eb..53671dfac15 100644
--- a/sdk_nnbd/lib/web_gl/dart2js/web_gl_dart2js.dart
+++ b/sdk_nnbd/lib/web_gl/dart2js/web_gl_dart2js.dart
@@ -86,10 +86,10 @@ class Canvas extends Interceptor {
   }
 
   @JSName('canvas')
-  final CanvasElement canvas;
+  CanvasElement get canvas native;
 
   @JSName('canvas')
-  final OffscreenCanvas offscreenCanvas;
+  OffscreenCanvas get offscreenCanvas native;
 }
 
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
diff --git a/tools/dom/scripts/css_code_generator.py b/tools/dom/scripts/css_code_generator.py
index 9459b58288a..2d7ac7b89af 100644
--- a/tools/dom/scripts/css_code_generator.py
+++ b/tools/dom/scripts/css_code_generator.py
@@ -203,7 +203,7 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME $EXTENDS with
    * Checks to see if CSS Transitions are supported.
    */
   static bool get supportsTransitions {
-    return document.body.style.supportsProperty('transition');
+    return document.body$NULLASSERT.style.supportsProperty('transition');
   }
 $!MEMBERS
 """)
@@ -220,9 +220,12 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('%s')
-  String _%s;
+  String get _%s native;
+
+  @JSName('%s')
+  set _%s(String value) native;
     """ % (property, camelName, camelName, property, camelName, camelName,
-           camelName, camelName))
+           camelName, camelName, camelName, camelName))
 
     class_file.write("""
 }
diff --git a/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate b/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate
index e34ea4c61d7..aa5f3e1f0a7 100644
--- a/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate
+++ b/tools/dom/templates/html/dart2js/impl_KeyboardEvent.darttemplate
@@ -63,9 +63,9 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
     }
   }
 
-  final int keyCode;
+  int get keyCode native;
 
-  final int charCode;
+  int get charCode native;
 
   int get which => _which;
 $!MEMBERS
diff --git a/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate b/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
index 292bafd84e9..914faca76a3 100644
--- a/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
+++ b/tools/dom/templates/html/impl/impl_CSSStyleDeclaration.darttemplate
@@ -105,7 +105,7 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME $EXTENDS with
    * Checks to see if CSS Transitions are supported.
    */
   static bool get supportsTransitions {
-    return document.body.style.supportsProperty('transition');
+    return document.body$NULLASSERT.style.supportsProperty('transition');
   }
 $!MEMBERS
 
@@ -118,7 +118,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('background')
-  String _background;
+  String get _background native;
+
+  @JSName('background')
+  set _background(String value) native;
     
   /** Gets the value of "background-attachment" */
   String get backgroundAttachment => this._backgroundAttachment;
@@ -129,7 +132,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('backgroundAttachment')
-  String _backgroundAttachment;
+  String get _backgroundAttachment native;
+
+  @JSName('backgroundAttachment')
+  set _backgroundAttachment(String value) native;
     
   /** Gets the value of "background-color" */
   String get backgroundColor => this._backgroundColor;
@@ -140,7 +146,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('backgroundColor')
-  String _backgroundColor;
+  String get _backgroundColor native;
+
+  @JSName('backgroundColor')
+  set _backgroundColor(String value) native;
     
   /** Gets the value of "background-image" */
   String get backgroundImage => this._backgroundImage;
@@ -151,7 +160,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('backgroundImage')
-  String _backgroundImage;
+  String get _backgroundImage native;
+
+  @JSName('backgroundImage')
+  set _backgroundImage(String value) native;
     
   /** Gets the value of "background-position" */
   String get backgroundPosition => this._backgroundPosition;
@@ -162,7 +174,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('backgroundPosition')
-  String _backgroundPosition;
+  String get _backgroundPosition native;
+
+  @JSName('backgroundPosition')
+  set _backgroundPosition(String value) native;
     
   /** Gets the value of "background-repeat" */
   String get backgroundRepeat => this._backgroundRepeat;
@@ -173,7 +188,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('backgroundRepeat')
-  String _backgroundRepeat;
+  String get _backgroundRepeat native;
+
+  @JSName('backgroundRepeat')
+  set _backgroundRepeat(String value) native;
     
   /** Gets the value of "border" */
   String get border => this._border;
@@ -184,7 +202,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('border')
-  String _border;
+  String get _border native;
+
+  @JSName('border')
+  set _border(String value) native;
     
   /** Gets the value of "border-bottom" */
   String get borderBottom => this._borderBottom;
@@ -195,7 +216,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderBottom')
-  String _borderBottom;
+  String get _borderBottom native;
+
+  @JSName('borderBottom')
+  set _borderBottom(String value) native;
     
   /** Gets the value of "border-bottom-color" */
   String get borderBottomColor => this._borderBottomColor;
@@ -206,7 +230,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderBottomColor')
-  String _borderBottomColor;
+  String get _borderBottomColor native;
+
+  @JSName('borderBottomColor')
+  set _borderBottomColor(String value) native;
     
   /** Gets the value of "border-bottom-style" */
   String get borderBottomStyle => this._borderBottomStyle;
@@ -217,7 +244,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderBottomStyle')
-  String _borderBottomStyle;
+  String get _borderBottomStyle native;
+
+  @JSName('borderBottomStyle')
+  set _borderBottomStyle(String value) native;
     
   /** Gets the value of "border-bottom-width" */
   String get borderBottomWidth => this._borderBottomWidth;
@@ -228,7 +258,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderBottomWidth')
-  String _borderBottomWidth;
+  String get _borderBottomWidth native;
+
+  @JSName('borderBottomWidth')
+  set _borderBottomWidth(String value) native;
     
   /** Gets the value of "border-collapse" */
   String get borderCollapse => this._borderCollapse;
@@ -239,7 +272,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderCollapse')
-  String _borderCollapse;
+  String get _borderCollapse native;
+
+  @JSName('borderCollapse')
+  set _borderCollapse(String value) native;
     
   /** Gets the value of "border-color" */
   String get borderColor => this._borderColor;
@@ -250,7 +286,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderColor')
-  String _borderColor;
+  String get _borderColor native;
+
+  @JSName('borderColor')
+  set _borderColor(String value) native;
     
   /** Gets the value of "border-left" */
   String get borderLeft => this._borderLeft;
@@ -261,7 +300,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderLeft')
-  String _borderLeft;
+  String get _borderLeft native;
+
+  @JSName('borderLeft')
+  set _borderLeft(String value) native;
     
   /** Gets the value of "border-left-color" */
   String get borderLeftColor => this._borderLeftColor;
@@ -272,7 +314,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderLeftColor')
-  String _borderLeftColor;
+  String get _borderLeftColor native;
+
+  @JSName('borderLeftColor')
+  set _borderLeftColor(String value) native;
     
   /** Gets the value of "border-left-style" */
   String get borderLeftStyle => this._borderLeftStyle;
@@ -283,7 +328,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderLeftStyle')
-  String _borderLeftStyle;
+  String get _borderLeftStyle native;
+
+  @JSName('borderLeftStyle')
+  set _borderLeftStyle(String value) native;
     
   /** Gets the value of "border-left-width" */
   String get borderLeftWidth => this._borderLeftWidth;
@@ -294,7 +342,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderLeftWidth')
-  String _borderLeftWidth;
+  String get _borderLeftWidth native;
+
+  @JSName('borderLeftWidth')
+  set _borderLeftWidth(String value) native;
     
   /** Gets the value of "border-right" */
   String get borderRight => this._borderRight;
@@ -305,7 +356,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderRight')
-  String _borderRight;
+  String get _borderRight native;
+
+  @JSName('borderRight')
+  set _borderRight(String value) native;
     
   /** Gets the value of "border-right-color" */
   String get borderRightColor => this._borderRightColor;
@@ -316,7 +370,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderRightColor')
-  String _borderRightColor;
+  String get _borderRightColor native;
+
+  @JSName('borderRightColor')
+  set _borderRightColor(String value) native;
     
   /** Gets the value of "border-right-style" */
   String get borderRightStyle => this._borderRightStyle;
@@ -327,7 +384,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderRightStyle')
-  String _borderRightStyle;
+  String get _borderRightStyle native;
+
+  @JSName('borderRightStyle')
+  set _borderRightStyle(String value) native;
     
   /** Gets the value of "border-right-width" */
   String get borderRightWidth => this._borderRightWidth;
@@ -338,7 +398,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderRightWidth')
-  String _borderRightWidth;
+  String get _borderRightWidth native;
+
+  @JSName('borderRightWidth')
+  set _borderRightWidth(String value) native;
     
   /** Gets the value of "border-spacing" */
   String get borderSpacing => this._borderSpacing;
@@ -349,7 +412,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderSpacing')
-  String _borderSpacing;
+  String get _borderSpacing native;
+
+  @JSName('borderSpacing')
+  set _borderSpacing(String value) native;
     
   /** Gets the value of "border-style" */
   String get borderStyle => this._borderStyle;
@@ -360,7 +426,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderStyle')
-  String _borderStyle;
+  String get _borderStyle native;
+
+  @JSName('borderStyle')
+  set _borderStyle(String value) native;
     
   /** Gets the value of "border-top" */
   String get borderTop => this._borderTop;
@@ -371,7 +440,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderTop')
-  String _borderTop;
+  String get _borderTop native;
+
+  @JSName('borderTop')
+  set _borderTop(String value) native;
     
   /** Gets the value of "border-top-color" */
   String get borderTopColor => this._borderTopColor;
@@ -382,7 +454,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderTopColor')
-  String _borderTopColor;
+  String get _borderTopColor native;
+
+  @JSName('borderTopColor')
+  set _borderTopColor(String value) native;
     
   /** Gets the value of "border-top-style" */
   String get borderTopStyle => this._borderTopStyle;
@@ -393,7 +468,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderTopStyle')
-  String _borderTopStyle;
+  String get _borderTopStyle native;
+
+  @JSName('borderTopStyle')
+  set _borderTopStyle(String value) native;
     
   /** Gets the value of "border-top-width" */
   String get borderTopWidth => this._borderTopWidth;
@@ -404,7 +482,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderTopWidth')
-  String _borderTopWidth;
+  String get _borderTopWidth native;
+
+  @JSName('borderTopWidth')
+  set _borderTopWidth(String value) native;
     
   /** Gets the value of "border-width" */
   String get borderWidth => this._borderWidth;
@@ -415,7 +496,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('borderWidth')
-  String _borderWidth;
+  String get _borderWidth native;
+
+  @JSName('borderWidth')
+  set _borderWidth(String value) native;
     
   /** Gets the value of "bottom" */
   String get bottom => this._bottom;
@@ -426,7 +510,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('bottom')
-  String _bottom;
+  String get _bottom native;
+
+  @JSName('bottom')
+  set _bottom(String value) native;
     
   /** Gets the value of "caption-side" */
   String get captionSide => this._captionSide;
@@ -437,7 +524,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('captionSide')
-  String _captionSide;
+  String get _captionSide native;
+
+  @JSName('captionSide')
+  set _captionSide(String value) native;
     
   /** Gets the value of "clear" */
   String get clear => this._clear;
@@ -448,7 +538,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('clear')
-  String _clear;
+  String get _clear native;
+
+  @JSName('clear')
+  set _clear(String value) native;
     
   /** Gets the value of "clip" */
   String get clip => this._clip;
@@ -459,7 +552,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('clip')
-  String _clip;
+  String get _clip native;
+
+  @JSName('clip')
+  set _clip(String value) native;
     
   /** Gets the value of "color" */
   String get color => this._color;
@@ -470,7 +566,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('color')
-  String _color;
+  String get _color native;
+
+  @JSName('color')
+  set _color(String value) native;
     
   /** Gets the value of "content" */
   String get content => this._content;
@@ -481,7 +580,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('content')
-  String _content;
+  String get _content native;
+
+  @JSName('content')
+  set _content(String value) native;
     
   /** Gets the value of "cursor" */
   String get cursor => this._cursor;
@@ -492,7 +594,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('cursor')
-  String _cursor;
+  String get _cursor native;
+
+  @JSName('cursor')
+  set _cursor(String value) native;
     
   /** Gets the value of "direction" */
   String get direction => this._direction;
@@ -503,7 +608,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('direction')
-  String _direction;
+  String get _direction native;
+
+  @JSName('direction')
+  set _direction(String value) native;
     
   /** Gets the value of "display" */
   String get display => this._display;
@@ -514,7 +622,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('display')
-  String _display;
+  String get _display native;
+
+  @JSName('display')
+  set _display(String value) native;
     
   /** Gets the value of "empty-cells" */
   String get emptyCells => this._emptyCells;
@@ -525,7 +636,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('emptyCells')
-  String _emptyCells;
+  String get _emptyCells native;
+
+  @JSName('emptyCells')
+  set _emptyCells(String value) native;
     
   /** Gets the value of "font" */
   String get font => this._font;
@@ -536,7 +650,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('font')
-  String _font;
+  String get _font native;
+
+  @JSName('font')
+  set _font(String value) native;
     
   /** Gets the value of "font-family" */
   String get fontFamily => this._fontFamily;
@@ -547,7 +664,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('fontFamily')
-  String _fontFamily;
+  String get _fontFamily native;
+
+  @JSName('fontFamily')
+  set _fontFamily(String value) native;
     
   /** Gets the value of "font-size" */
   String get fontSize => this._fontSize;
@@ -558,7 +678,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('fontSize')
-  String _fontSize;
+  String get _fontSize native;
+
+  @JSName('fontSize')
+  set _fontSize(String value) native;
     
   /** Gets the value of "font-style" */
   String get fontStyle => this._fontStyle;
@@ -569,7 +692,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('fontStyle')
-  String _fontStyle;
+  String get _fontStyle native;
+
+  @JSName('fontStyle')
+  set _fontStyle(String value) native;
     
   /** Gets the value of "font-variant" */
   String get fontVariant => this._fontVariant;
@@ -580,7 +706,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('fontVariant')
-  String _fontVariant;
+  String get _fontVariant native;
+
+  @JSName('fontVariant')
+  set _fontVariant(String value) native;
     
   /** Gets the value of "font-weight" */
   String get fontWeight => this._fontWeight;
@@ -591,7 +720,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('fontWeight')
-  String _fontWeight;
+  String get _fontWeight native;
+
+  @JSName('fontWeight')
+  set _fontWeight(String value) native;
     
   /** Gets the value of "height" */
   String get height => this._height;
@@ -602,7 +734,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('height')
-  String _height;
+  String get _height native;
+
+  @JSName('height')
+  set _height(String value) native;
     
   /** Gets the value of "left" */
   String get left => this._left;
@@ -613,7 +748,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('left')
-  String _left;
+  String get _left native;
+
+  @JSName('left')
+  set _left(String value) native;
     
   /** Gets the value of "letter-spacing" */
   String get letterSpacing => this._letterSpacing;
@@ -624,7 +762,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('letterSpacing')
-  String _letterSpacing;
+  String get _letterSpacing native;
+
+  @JSName('letterSpacing')
+  set _letterSpacing(String value) native;
     
   /** Gets the value of "line-height" */
   String get lineHeight => this._lineHeight;
@@ -635,7 +776,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('lineHeight')
-  String _lineHeight;
+  String get _lineHeight native;
+
+  @JSName('lineHeight')
+  set _lineHeight(String value) native;
     
   /** Gets the value of "list-style" */
   String get listStyle => this._listStyle;
@@ -646,7 +790,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('listStyle')
-  String _listStyle;
+  String get _listStyle native;
+
+  @JSName('listStyle')
+  set _listStyle(String value) native;
     
   /** Gets the value of "list-style-image" */
   String get listStyleImage => this._listStyleImage;
@@ -657,7 +804,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('listStyleImage')
-  String _listStyleImage;
+  String get _listStyleImage native;
+
+  @JSName('listStyleImage')
+  set _listStyleImage(String value) native;
     
   /** Gets the value of "list-style-position" */
   String get listStylePosition => this._listStylePosition;
@@ -668,7 +818,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('listStylePosition')
-  String _listStylePosition;
+  String get _listStylePosition native;
+
+  @JSName('listStylePosition')
+  set _listStylePosition(String value) native;
     
   /** Gets the value of "list-style-type" */
   String get listStyleType => this._listStyleType;
@@ -679,7 +832,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('listStyleType')
-  String _listStyleType;
+  String get _listStyleType native;
+
+  @JSName('listStyleType')
+  set _listStyleType(String value) native;
     
   /** Gets the value of "margin" */
   String get margin => this._margin;
@@ -690,7 +846,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('margin')
-  String _margin;
+  String get _margin native;
+
+  @JSName('margin')
+  set _margin(String value) native;
     
   /** Gets the value of "margin-bottom" */
   String get marginBottom => this._marginBottom;
@@ -701,7 +860,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('marginBottom')
-  String _marginBottom;
+  String get _marginBottom native;
+
+  @JSName('marginBottom')
+  set _marginBottom(String value) native;
     
   /** Gets the value of "margin-left" */
   String get marginLeft => this._marginLeft;
@@ -712,7 +874,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('marginLeft')
-  String _marginLeft;
+  String get _marginLeft native;
+
+  @JSName('marginLeft')
+  set _marginLeft(String value) native;
     
   /** Gets the value of "margin-right" */
   String get marginRight => this._marginRight;
@@ -723,7 +888,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('marginRight')
-  String _marginRight;
+  String get _marginRight native;
+
+  @JSName('marginRight')
+  set _marginRight(String value) native;
     
   /** Gets the value of "margin-top" */
   String get marginTop => this._marginTop;
@@ -734,7 +902,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('marginTop')
-  String _marginTop;
+  String get _marginTop native;
+
+  @JSName('marginTop')
+  set _marginTop(String value) native;
     
   /** Gets the value of "max-height" */
   String get maxHeight => this._maxHeight;
@@ -745,7 +916,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('maxHeight')
-  String _maxHeight;
+  String get _maxHeight native;
+
+  @JSName('maxHeight')
+  set _maxHeight(String value) native;
     
   /** Gets the value of "max-width" */
   String get maxWidth => this._maxWidth;
@@ -756,7 +930,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('maxWidth')
-  String _maxWidth;
+  String get _maxWidth native;
+
+  @JSName('maxWidth')
+  set _maxWidth(String value) native;
     
   /** Gets the value of "min-height" */
   String get minHeight => this._minHeight;
@@ -767,7 +944,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('minHeight')
-  String _minHeight;
+  String get _minHeight native;
+
+  @JSName('minHeight')
+  set _minHeight(String value) native;
     
   /** Gets the value of "min-width" */
   String get minWidth => this._minWidth;
@@ -778,7 +958,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('minWidth')
-  String _minWidth;
+  String get _minWidth native;
+
+  @JSName('minWidth')
+  set _minWidth(String value) native;
     
   /** Gets the value of "outline" */
   String get outline => this._outline;
@@ -789,7 +972,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('outline')
-  String _outline;
+  String get _outline native;
+
+  @JSName('outline')
+  set _outline(String value) native;
     
   /** Gets the value of "outline-color" */
   String get outlineColor => this._outlineColor;
@@ -800,7 +986,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('outlineColor')
-  String _outlineColor;
+  String get _outlineColor native;
+
+  @JSName('outlineColor')
+  set _outlineColor(String value) native;
     
   /** Gets the value of "outline-style" */
   String get outlineStyle => this._outlineStyle;
@@ -811,7 +1000,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('outlineStyle')
-  String _outlineStyle;
+  String get _outlineStyle native;
+
+  @JSName('outlineStyle')
+  set _outlineStyle(String value) native;
     
   /** Gets the value of "outline-width" */
   String get outlineWidth => this._outlineWidth;
@@ -822,7 +1014,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('outlineWidth')
-  String _outlineWidth;
+  String get _outlineWidth native;
+
+  @JSName('outlineWidth')
+  set _outlineWidth(String value) native;
     
   /** Gets the value of "overflow" */
   String get overflow => this._overflow;
@@ -833,7 +1028,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('overflow')
-  String _overflow;
+  String get _overflow native;
+
+  @JSName('overflow')
+  set _overflow(String value) native;
     
   /** Gets the value of "padding" */
   String get padding => this._padding;
@@ -844,7 +1042,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('padding')
-  String _padding;
+  String get _padding native;
+
+  @JSName('padding')
+  set _padding(String value) native;
     
   /** Gets the value of "padding-bottom" */
   String get paddingBottom => this._paddingBottom;
@@ -855,7 +1056,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('paddingBottom')
-  String _paddingBottom;
+  String get _paddingBottom native;
+
+  @JSName('paddingBottom')
+  set _paddingBottom(String value) native;
     
   /** Gets the value of "padding-left" */
   String get paddingLeft => this._paddingLeft;
@@ -866,7 +1070,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('paddingLeft')
-  String _paddingLeft;
+  String get _paddingLeft native;
+
+  @JSName('paddingLeft')
+  set _paddingLeft(String value) native;
     
   /** Gets the value of "padding-right" */
   String get paddingRight => this._paddingRight;
@@ -877,7 +1084,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('paddingRight')
-  String _paddingRight;
+  String get _paddingRight native;
+
+  @JSName('paddingRight')
+  set _paddingRight(String value) native;
     
   /** Gets the value of "padding-top" */
   String get paddingTop => this._paddingTop;
@@ -888,7 +1098,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('paddingTop')
-  String _paddingTop;
+  String get _paddingTop native;
+
+  @JSName('paddingTop')
+  set _paddingTop(String value) native;
     
   /** Gets the value of "page-break-after" */
   String get pageBreakAfter => this._pageBreakAfter;
@@ -899,7 +1112,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('pageBreakAfter')
-  String _pageBreakAfter;
+  String get _pageBreakAfter native;
+
+  @JSName('pageBreakAfter')
+  set _pageBreakAfter(String value) native;
     
   /** Gets the value of "page-break-before" */
   String get pageBreakBefore => this._pageBreakBefore;
@@ -910,7 +1126,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('pageBreakBefore')
-  String _pageBreakBefore;
+  String get _pageBreakBefore native;
+
+  @JSName('pageBreakBefore')
+  set _pageBreakBefore(String value) native;
     
   /** Gets the value of "page-break-inside" */
   String get pageBreakInside => this._pageBreakInside;
@@ -921,7 +1140,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('pageBreakInside')
-  String _pageBreakInside;
+  String get _pageBreakInside native;
+
+  @JSName('pageBreakInside')
+  set _pageBreakInside(String value) native;
     
   /** Gets the value of "position" */
   String get position => this._position;
@@ -932,7 +1154,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('position')
-  String _position;
+  String get _position native;
+
+  @JSName('position')
+  set _position(String value) native;
     
   /** Gets the value of "quotes" */
   String get quotes => this._quotes;
@@ -943,7 +1168,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('quotes')
-  String _quotes;
+  String get _quotes native;
+
+  @JSName('quotes')
+  set _quotes(String value) native;
     
   /** Gets the value of "right" */
   String get right => this._right;
@@ -954,7 +1182,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('right')
-  String _right;
+  String get _right native;
+
+  @JSName('right')
+  set _right(String value) native;
     
   /** Gets the value of "table-layout" */
   String get tableLayout => this._tableLayout;
@@ -965,7 +1196,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('tableLayout')
-  String _tableLayout;
+  String get _tableLayout native;
+
+  @JSName('tableLayout')
+  set _tableLayout(String value) native;
     
   /** Gets the value of "text-align" */
   String get textAlign => this._textAlign;
@@ -976,7 +1210,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('textAlign')
-  String _textAlign;
+  String get _textAlign native;
+
+  @JSName('textAlign')
+  set _textAlign(String value) native;
     
   /** Gets the value of "text-decoration" */
   String get textDecoration => this._textDecoration;
@@ -987,7 +1224,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('textDecoration')
-  String _textDecoration;
+  String get _textDecoration native;
+
+  @JSName('textDecoration')
+  set _textDecoration(String value) native;
     
   /** Gets the value of "text-indent" */
   String get textIndent => this._textIndent;
@@ -998,7 +1238,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('textIndent')
-  String _textIndent;
+  String get _textIndent native;
+
+  @JSName('textIndent')
+  set _textIndent(String value) native;
     
   /** Gets the value of "text-transform" */
   String get textTransform => this._textTransform;
@@ -1009,7 +1252,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('textTransform')
-  String _textTransform;
+  String get _textTransform native;
+
+  @JSName('textTransform')
+  set _textTransform(String value) native;
     
   /** Gets the value of "top" */
   String get top => this._top;
@@ -1020,7 +1266,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('top')
-  String _top;
+  String get _top native;
+
+  @JSName('top')
+  set _top(String value) native;
     
   /** Gets the value of "unicode-bidi" */
   String get unicodeBidi => this._unicodeBidi;
@@ -1031,7 +1280,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('unicodeBidi')
-  String _unicodeBidi;
+  String get _unicodeBidi native;
+
+  @JSName('unicodeBidi')
+  set _unicodeBidi(String value) native;
     
   /** Gets the value of "vertical-align" */
   String get verticalAlign => this._verticalAlign;
@@ -1042,7 +1294,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('verticalAlign')
-  String _verticalAlign;
+  String get _verticalAlign native;
+
+  @JSName('verticalAlign')
+  set _verticalAlign(String value) native;
     
   /** Gets the value of "visibility" */
   String get visibility => this._visibility;
@@ -1053,7 +1308,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('visibility')
-  String _visibility;
+  String get _visibility native;
+
+  @JSName('visibility')
+  set _visibility(String value) native;
     
   /** Gets the value of "white-space" */
   String get whiteSpace => this._whiteSpace;
@@ -1064,7 +1322,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('whiteSpace')
-  String _whiteSpace;
+  String get _whiteSpace native;
+
+  @JSName('whiteSpace')
+  set _whiteSpace(String value) native;
     
   /** Gets the value of "width" */
   String get width => this._width;
@@ -1075,7 +1336,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('width')
-  String _width;
+  String get _width native;
+
+  @JSName('width')
+  set _width(String value) native;
     
   /** Gets the value of "word-spacing" */
   String get wordSpacing => this._wordSpacing;
@@ -1086,7 +1350,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('wordSpacing')
-  String _wordSpacing;
+  String get _wordSpacing native;
+
+  @JSName('wordSpacing')
+  set _wordSpacing(String value) native;
     
   /** Gets the value of "z-index" */
   String get zIndex => this._zIndex;
@@ -1097,7 +1364,10 @@ $!MEMBERS
   }
   @Returns('String')
   @JSName('zIndex')
-  String _zIndex;
+  String get _zIndex native;
+
+  @JSName('zIndex')
+  set _zIndex(String value) native;
     
 }
 
diff --git a/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate b/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate
index 9f971612232..d2b2c9dd01e 100644
--- a/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate
+++ b/tools/dom/templates/html/impl/impl_DocumentFragment.darttemplate
@@ -11,7 +11,7 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
       {NodeValidator$NULLABLE validator,
        NodeTreeSanitizer$NULLABLE treeSanitizer}) {
 
-    return document.body.createFragment(html,
+    return document.body$NULLASSERT.createFragment(html,
       validator: validator, treeSanitizer: treeSanitizer);
   }
 
@@ -75,7 +75,7 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
      NodeTreeSanitizer$NULLABLE treeSanitizer}) {
 
     this.nodes.clear();
-    append(document.body.createFragment(
+    append(document.body$NULLASSERT.createFragment(
         html, validator: validator, treeSanitizer: treeSanitizer));
   }
 
diff --git a/tools/dom/templates/html/impl/impl_Element.darttemplate b/tools/dom/templates/html/impl/impl_Element.darttemplate
index 9963dbad002..3b427aa21e2 100644
--- a/tools/dom/templates/html/impl/impl_Element.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Element.darttemplate
@@ -348,8 +348,8 @@ $(ANNOTATIONS)$(NATIVESPEC)class $CLASSNAME$EXTENDS$IMPLEMENTS {
   factory Element.html(String html,
       {NodeValidator$NULLABLE validator,
        NodeTreeSanitizer$NULLABLE treeSanitizer}) {
-    var fragment = document.body.createFragment(html, validator: validator,
-        treeSanitizer: treeSanitizer);
+    var fragment = document.body$NULLASSERT.createFragment(html,
+        validator: validator, treeSanitizer: treeSanitizer);
 
     return fragment.nodes.where((e) => e is Element).single $#NULLSAFECAST(as Element);
   }
@@ -1336,10 +1336,10 @@ $(ANNOTATIONS)$(NATIVESPEC)class $CLASSNAME$EXTENDS$IMPLEMENTS {
 
     var contextElement;
     if (this is BodyElement) {
-      contextElement = _parseDocument$NULLASSERT.body;
+      contextElement = _parseDocument$NULLASSERT.body$NULLASSERT;
     } else {
       contextElement = _parseDocument$NULLASSERT.createElement(tagName);
-      _parseDocument$NULLASSERT.body.append(contextElement);
+      _parseDocument$NULLASSERT.body$NULLASSERT.append(contextElement);
     }
     var fragment;
     if (Range.supportsCreateContextualFragment &&
diff --git a/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate b/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
index 4401781036a..5da7c9b9076 100644
--- a/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
+++ b/tools/dom/templates/html/impl/impl_HTMLDocument.darttemplate
@@ -9,7 +9,8 @@ part of $LIBRARYNAME;
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
 $!MEMBERS
 
-  BodyElement body;
+  BodyElement$NULLABLE get body native;
+  set body(BodyElement$NULLABLE value) native;
 
   /// UNSTABLE: Chrome-only - create a Range from the given point.
   @Unstable()
diff --git a/tools/dom/templates/html/impl/impl_HTMLInputElement.darttemplate b/tools/dom/templates/html/impl/impl_HTMLInputElement.darttemplate
index fb81a0ab484..6135de6c0c7 100644
--- a/tools/dom/templates/html/impl/impl_HTMLInputElement.darttemplate
+++ b/tools/dom/templates/html/impl/impl_HTMLInputElement.darttemplate
@@ -170,7 +170,8 @@ $endif
 abstract class SearchInputElement implements TextInputElementBase {
   factory SearchInputElement() => new InputElement(type: 'search');
 
-  String dirName;
+  String get dirName;
+  set dirName(String value);
 
   Element$NULLABLE get list;
 
@@ -186,7 +187,8 @@ abstract class SearchInputElement implements TextInputElementBase {
 abstract class TextInputElement implements TextInputElementBase {
   factory TextInputElement() => new InputElement(type: 'text');
 
-  String dirName;
+  String get dirName;
+  set dirName(String value);
 
   Element$NULLABLE get list;
 }
@@ -246,25 +248,34 @@ abstract class TelephoneInputElement implements TextInputElementBase {
 abstract class EmailInputElement implements TextInputElementBase {
   factory EmailInputElement() => new InputElement(type: 'email');
 
-  String autocomplete;
+  String get autocomplete;
+  set autocomplete(String value);
 
-  bool autofocus;
+  bool get autofocus;
+  set autofocus(bool value);
 
   Element$NULLABLE get list;
 
-  int maxLength;
+  int get maxLength;
+  set maxLength(int value);
 
-  bool multiple;
+  bool get multiple;
+  set multiple(bool value);
 
-  String pattern;
+  String get pattern;
+  set pattern(String value);
 
-  String placeholder;
+  String get placeholder;
+  set placeholder(String value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
-  int size;
+  int get size;
+  set size(int value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -322,11 +333,14 @@ $endif
 abstract class DateInputElement implements RangeInputElementBase {
   factory DateInputElement() => new InputElement(type: 'date');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -343,11 +357,14 @@ abstract class DateInputElement implements RangeInputElementBase {
 abstract class MonthInputElement implements RangeInputElementBase {
   factory MonthInputElement() => new InputElement(type: 'month');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -364,11 +381,14 @@ abstract class MonthInputElement implements RangeInputElementBase {
 abstract class WeekInputElement implements RangeInputElementBase {
   factory WeekInputElement() => new InputElement(type: 'week');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -385,11 +405,14 @@ abstract class WeekInputElement implements RangeInputElementBase {
 abstract class TimeInputElement implements RangeInputElementBase {
   factory TimeInputElement() => new InputElement(type: 'time');
 
-  DateTime valueAsDate;
+  DateTime get valueAsDate;
+  set valueAsDate(DateTime value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -408,9 +431,11 @@ abstract class LocalDateTimeInputElement implements RangeInputElementBase {
   factory LocalDateTimeInputElement() =>
       new InputElement(type: 'datetime-local');
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -427,11 +452,14 @@ abstract class LocalDateTimeInputElement implements RangeInputElementBase {
 abstract class NumberInputElement implements RangeInputElementBase {
   factory NumberInputElement() => new InputElement(type: 'number');
 
-  String placeholder;
+  String get placeholder;
+  set placeholder(String value);
 
-  bool readOnly;
+  bool get readOnly;
+  set readOnly(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   /// Returns true if this input type is supported on the current platform.
   static bool get supported {
@@ -465,9 +493,11 @@ abstract class RangeInputElement implements RangeInputElementBase {
 abstract class CheckboxInputElement implements InputElementBase {
   factory CheckboxInputElement() => new InputElement(type: 'checkbox');
 
-  bool checked;
+  bool get checked;
+  set checked(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 }
 
 
@@ -485,9 +515,11 @@ abstract class CheckboxInputElement implements InputElementBase {
 abstract class RadioButtonInputElement implements InputElementBase {
   factory RadioButtonInputElement() => new InputElement(type: 'radio');
 
-  bool checked;
+  bool get checked;
+  set checked(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 }
 
 /**
@@ -496,11 +528,14 @@ abstract class RadioButtonInputElement implements InputElementBase {
 abstract class FileUploadInputElement implements InputElementBase {
   factory FileUploadInputElement() => new InputElement(type: 'file');
 
-  String accept;
+  String get accept;
+  set accept(String value);
 
-  bool multiple;
+  bool get multiple;
+  set multiple(bool value);
 
-  bool required;
+  bool get required;
+  set required(bool value);
 
   List<File>$NULLABLE files;
 }
@@ -511,15 +546,20 @@ abstract class FileUploadInputElement implements InputElementBase {
 abstract class SubmitButtonInputElement implements InputElementBase {
   factory SubmitButtonInputElement() => new InputElement(type: 'submit');
 
-  String formAction;
+  String get formAction;
+  set formAction(String value);
 
-  String formEnctype;
+  String get formEnctype;
+  set formEnctype(String value);
 
-  String formMethod;
+  String get formMethod;
+  set formMethod(String value);
 
-  bool formNoValidate;
+  bool get formNoValidate;
+  set formNoValidate(bool value);
 
-  String formTarget;
+  String get formTarget;
+  set formTarget(String value);
 }
 
 /**
@@ -529,23 +569,32 @@ abstract class SubmitButtonInputElement implements InputElementBase {
 abstract class ImageButtonInputElement implements InputElementBase {
   factory ImageButtonInputElement() => new InputElement(type: 'image');
 
-  String alt;
+  String get alt;
+  set alt(String value);
 
-  String formAction;
+  String get formAction;
+  set formAction(String value);
 
-  String formEnctype;
+  String get formEnctype;
+  set formEnctype(String value);
 
-  String formMethod;
+  String get formMethod;
+  set formMethod(String value);
 
-  bool formNoValidate;
+  bool get formNoValidate;
+  set formNoValidate(bool value);
 
-  String formTarget;
+  String get formTarget;
+  set formTarget(String value);
 
-  int height;
+  int get height;
+  set height(int value);
 
-  String src;
+  String get src;
+  set src(String value);
 
-  int width;
+  int get width;
+  set width(int value);
 }
 
 /**
diff --git a/tools/dom/templates/html/impl/impl_IDBVersionChangeEvent.darttemplate b/tools/dom/templates/html/impl/impl_IDBVersionChangeEvent.darttemplate
index f93d07e74f7..c2741b942c2 100644
--- a/tools/dom/templates/html/impl/impl_IDBVersionChangeEvent.darttemplate
+++ b/tools/dom/templates/html/impl/impl_IDBVersionChangeEvent.darttemplate
@@ -7,6 +7,6 @@ part of $LIBRARYNAME;
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
 $!MEMBERS
   @JSName('target')
-  final OpenDBRequest target;
+  OpenDBRequest get target native;
 }
 
diff --git a/tools/dom/templates/html/impl/impl_MessageEvent.darttemplate b/tools/dom/templates/html/impl/impl_MessageEvent.darttemplate
index 3c690acb11c..e98d7445349 100644
--- a/tools/dom/templates/html/impl/impl_MessageEvent.darttemplate
+++ b/tools/dom/templates/html/impl/impl_MessageEvent.darttemplate
@@ -35,7 +35,7 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
   @JSName('data')
   @annotation_Creates_SerializedScriptValue
   @annotation_Returns_SerializedScriptValue
-  final dynamic _get_data;
+  dynamic get _get_data native;
 
 $!MEMBERS
 }
diff --git a/tools/dom/templates/html/impl/impl_SVGElement.darttemplate b/tools/dom/templates/html/impl/impl_SVGElement.darttemplate
index 9934ddbd397..1e6636565b0 100644
--- a/tools/dom/templates/html/impl/impl_SVGElement.darttemplate
+++ b/tools/dom/templates/html/impl/impl_SVGElement.darttemplate
@@ -100,7 +100,7 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
 
     // We create a fragment which will parse in the HTML parser
     var html = '<svg version="1.1">$svg</svg>';
-    var fragment = document.body.createFragment(html,
+    var fragment = document.body$NULLASSERT.createFragment(html,
         treeSanitizer: treeSanitizer);
 
     var svgFragment = new DocumentFragment();
diff --git a/tools/dom/templates/html/impl/impl_ServiceWorkerMessageEvent.darttemplate b/tools/dom/templates/html/impl/impl_ServiceWorkerMessageEvent.darttemplate
index 2df0f3bddf9..c8bd286cfa3 100644
--- a/tools/dom/templates/html/impl/impl_ServiceWorkerMessageEvent.darttemplate
+++ b/tools/dom/templates/html/impl/impl_ServiceWorkerMessageEvent.darttemplate
@@ -18,7 +18,7 @@ $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS
   @JSName('data')
   @annotation_Creates_SerializedScriptValue
   @annotation_Returns_SerializedScriptValue
-  final dynamic _get_data;
+  dynamic get _get_data native;
 
 $!MEMBERS
 }
diff --git a/tools/dom/templates/html/impl/impl_WebGLCanvas.darttemplate b/tools/dom/templates/html/impl/impl_WebGLCanvas.darttemplate
index a4730dc98b5..2909b4dde83 100644
--- a/tools/dom/templates/html/impl/impl_WebGLCanvas.darttemplate
+++ b/tools/dom/templates/html/impl/impl_WebGLCanvas.darttemplate
@@ -8,9 +8,9 @@ $(ANNOTATIONS)$(NATIVESPEC)class $CLASSNAME$EXTENDS {
 $!MEMBERS
 
   @JSName('canvas')
-  final CanvasElement canvas;
+  CanvasElement get canvas native;
 
   @JSName('canvas')
-  final OffscreenCanvas offscreenCanvas;
+  OffscreenCanvas get offscreenCanvas native;
 }