[dart2js] Migrate developer patch file to nnbd.

Note: This is mostly just the DDC developer patch file.
Change-Id: I98277304b2fbe8fa939dc7e6fb4bd9e0c199b2b0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/135535
Commit-Queue: Joshua Litt <joshualitt@google.com>
Reviewed-by: Sigmund Cherem <sigmund@google.com>

pkg/dev_compiler/tool/dart2js_nnbd_sdk_error_golden.txt

@@ -1,3 +1,4 @@
+ERROR|COMPILE_TIME_ERROR|CONST_EVAL_THROWS_EXCEPTION|lib/developer/developer.dart|522|5|73|Evaluation of this constant expression throws an exception.
 ERROR|COMPILE_TIME_ERROR|EXPORT_LEGACY_SYMBOL|lib/html/dart2js/html_dart2js.dart|70|8|18|The symbol 'promiseToFuture' is defined in a legacy library, and can't be re-exported from a non-nullable by default library.
 ERROR|COMPILE_TIME_ERROR|EXPORT_LEGACY_SYMBOL|lib/html/html_common/html_common_dart2js.dart|19|8|14|The symbol 'promiseToFuture' is defined in a legacy library, and can't be re-exported from a non-nullable by default library.
 ERROR|COMPILE_TIME_ERROR|INCONSISTENT_INHERITANCE|lib/_internal/js_runtime/lib/interceptors.dart|1639|7|5|Superinterfaces don't have a valid override for '&': int.& (int* Function(int*)*), JSNumber.& (num Function(num)).

sdk_nnbd/lib/_internal/js_runtime/lib/developer_patch.dart

@@ -2,8 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// @dart = 2.5
-
 // Patch file for dart:developer library.
 
 import 'dart:_js_helper' show patch, ForceInline;
@@ -13,7 +11,7 @@ import 'dart:isolate';
 
 @patch
 @pragma('dart2js:tryInline')
-bool debugger({bool when: true, String message}) {
+bool debugger({bool when = true, String? message}) {
   if (when) {
     JS('', 'debugger');
   }
@@ -21,26 +19,26 @@ bool debugger({bool when: true, String message}) {
 }
 
 @patch
-Object inspect(Object object) {
+Object? inspect(Object? object) {
   return object;
 }
 
 @patch
 void log(String message,
-    {DateTime time,
-    int sequenceNumber,
-    int level: 0,
-    String name: '',
-    Zone zone,
-    Object error,
-    StackTrace stackTrace}) {
+    {DateTime? time,
+    int? sequenceNumber,
+    int level = 0,
+    String name = '',
+    Zone? zone,
+    Object? error,
+    StackTrace? stackTrace}) {
   // TODO.
 }
 
-final _extensions = new Map<String, ServiceExtensionHandler>();
+final _extensions = <String, ServiceExtensionHandler>{};
 
 @patch
-ServiceExtensionHandler _lookupExtension(String method) {
+ServiceExtensionHandler? _lookupExtension(String method) {
   return _extensions[method];
 }
 
@@ -110,7 +108,7 @@ void _webServerControl(SendPort sendPort, bool enable) {
 }
 
 @patch
-String _getIsolateIDFromSendPort(SendPort sendPort) {
+String? _getIsolateIDFromSendPort(SendPort sendPort) {
   return null;
 }
 
@@ -124,7 +122,7 @@ class UserTag {
 }
 
 class _FakeUserTag implements UserTag {
-  static Map _instances = {};
+  static final _instances = <String, _FakeUserTag>{};
 
   _FakeUserTag.real(this.label);
 
@@ -136,13 +134,10 @@ class _FakeUserTag implements UserTag {
     }
     // Throw an exception if we've reached the maximum number of user tags.
     if (_instances.length == UserTag.MAX_USER_TAGS) {
-      throw new UnsupportedError(
+      throw UnsupportedError(
           'UserTag instance limit (${UserTag.MAX_USER_TAGS}) reached.');
     }
-    // Create a new instance and add it to the instance map.
-    var instance = new _FakeUserTag.real(label);
-    _instances[label] = instance;
-    return instance;
+    return _instances[label] = _FakeUserTag.real(label);
   }
 
   final String label;

sdk_nnbd/lib/dart2js_migration_libraries.json

@@ -20,8 +20,8 @@
         "patches": "../../sdk/lib/_internal/js_runtime/lib/core_patch.dart"
       },
       "developer": {
-        "uri": "../../sdk/lib/developer/developer.dart",
-        "patches": "../../sdk/lib/_internal/js_runtime/lib/developer_patch.dart"
+        "uri": "developer/developer.dart",
+        "patches": "_internal/js_runtime/lib/developer_patch.dart"
       },
       "html": {
         "uri": "html/dart2js/html_dart2js.dart"