Trying to fix SQLResultSetRowList's subscript operator to do type conversion

BUG=

Review URL: https://codereview.chromium.org/1779023002 .

sdk/lib/web_sql/dart2js/web_sql_dart2js.dart

@@ -210,7 +210,7 @@ class SqlResultSet extends Interceptor {
 // http://www.w3.org/TR/webdatabase/#sqlresultsetrowlist
 @Experimental() // deprecated
 @Native("SQLResultSetRowList")
-class SqlResultSetRowList extends Interceptor with ListMixin<Map>, ImmutableListMixin<Map> implements JavaScriptIndexingBehavior, List<Map> {
+class SqlResultSetRowList extends Interceptor with ListMixin<Map>, ImmutableListMixin<Map> implements List<Map> {
   // To suppress missing implicit constructor warnings.
   factory SqlResultSetRowList._() { throw new UnsupportedError("Not supported"); }
 
@@ -222,7 +222,7 @@ class SqlResultSetRowList extends Interceptor with ListMixin<Map>, ImmutableList
     if (JS("bool", "# >>> 0 !== # || # >= #", index,
         index, index, length))
       throw new RangeError.index(index, this);
-    return JS("Map", "#[#]", this, index);
+    return this.item(index);
   }
   void operator[]=(int index, Map value) {
     throw new UnsupportedError("Cannot assign element of immutable List.");
@@ -264,8 +264,13 @@ class SqlResultSetRowList extends Interceptor with ListMixin<Map>, ImmutableList
 
   @DomName('SQLResultSetRowList.item')
   @DocsEditable()
-  @Creates('=Object')
-  Object item(int index) native;
+  Map item(int index) {
+    return convertNativeToDart_Dictionary(_item_1(index));
+  }
+  @JSName('item')
+  @DomName('SQLResultSetRowList.item')
+  @DocsEditable()
+  _item_1(index) native;
 }
 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a

tools/dom/dom.json

@@ -15095,6 +15095,12 @@
       },
       "encoding": {
         "support_level": "untriaged"
+      },
+      "fatal": {
+        "support_level": "untriaged"
+      },
+      "ignoreBOM": {
+        "support_level": "untriaged"
       }
     },
     "support_level": "untriaged"

tools/dom/scripts/dartmetadata.py

@@ -329,8 +329,6 @@ _dart2js_annotations = monitored.Dict('dartmetadata._dart2js_annotations', {
       "@Returns('NodeList|HtmlCollection')",
     ],
 
-    'SQLResultSetRowList.item': ["@Creates('=Object')"],
-
     # Touch targets are Elements in a Document, or the Document.
     'Touch.target': [
       "@Creates('Element|Document')",

tools/dom/scripts/generator.py

@@ -721,6 +721,9 @@ dart2js_conversions = monitored.Dict('generator.dart2js_conversions', {
     'any set IDBObjectStore.put': _serialize_SSV,
     'any set IDBCursor.update': _serialize_SSV,
 
+    'any get SQLResultSetRowList.item' :
+      Conversion('convertNativeToDart_Dictionary', 'dynamic', 'Map'),
+
     # postMessage
     'SerializedScriptValue set': _serialize_SSV,
     'any set CompositorWorkerGlobalScope.postMessage': _serialize_SSV,

tools/dom/scripts/systemhtml.py

@@ -828,7 +828,8 @@ class Dart2JSBackend(HtmlDartGenerator):
     ext_attrs = self._interface.ext_attrs
     has_indexed_getter = 'CustomIndexedGetter' in ext_attrs
     for operation in self._interface.operations:
-      if operation.id == 'item' and 'getter' in operation.specials:
+      if operation.id == 'item' and 'getter' in operation.specials \
+          and not self._OperationRequiresConversions(operation):
         has_indexed_getter = True
         break
     return has_indexed_getter