Fixing a number of Dart2JS compiler warnings.

tools/dom/src/dart2js_Conversions.dart

 // 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
 // BSD-style license that can be found in the LICENSE file.
 
 
 // Conversions for Window.  These check if the window is the local
 // window, and if it's not, wraps or unwraps it with a secure wrapper.
 // We need to test for EventTarget here as well as it's a base type.
 // We omit an unwrapper for Window as no methods take a non-local
 // window as a parameter.
@@ skipping 33 matching lines @@
     return e;
 }
 
 EventTarget _convertDartToNative_EventTarget(e) {
   if (e is _DOMWindowCrossFrame) {
     return e._window;
   } else {
     return e;
   }
 }
-
-// Conversions for ImageData
-//
-// On Firefox, the returned ImageData is a plain object.
-
-class _TypedImageData implements ImageData {
-  final Uint8ClampedList data;
-  final int height;
-  final int width;
-
-  _TypedImageData(this.data, this.height, this.width);
-}
-
-ImageData _convertNativeToDart_ImageData(nativeImageData) {
-
-  // None of the native getters that return ImageData have the type ImageData
-  // since that is incorrect for FireFox (which returns a plain Object).  So we
-  // need something that tells the compiler that the ImageData class has been
-  // instantiated.
-  // TODO(sra): Remove this when all the ImageData returning APIs have been
-  // annotated as returning the union ImageData + Object.
-  JS('ImageData', '0');
-
-  if (nativeImageData is ImageData) return nativeImageData;
-
-  // On Firefox the above test fails because imagedata is a plain object.
-  // So we create a _TypedImageData.
-
-  return new _TypedImageData(
-      JS('var', '#.data', nativeImageData),
-      JS('var', '#.height', nativeImageData),
-      JS('var', '#.width', nativeImageData));
-}
-
-// We can get rid of this conversion if _TypedImageData implements the fields
-// with native names.
-_convertDartToNative_ImageData(ImageData imageData) {
-  if (imageData is _TypedImageData) {
-    return JS('', '{data: #, height: #, width: #}',
-        imageData.data, imageData.height, imageData.width);
-  }
-  return imageData;
-}