Nuke CanvasPixelArray as it is dropped from WebKit as well.

lib/dom/dom.dart

Index: lib/dom/dom.dart
diff --git a/lib/dom/dom.dart b/lib/dom/dom.dart
index 28440cd09d13d641a601cf13d38c838c27869752..a9e896b5a792c5822ae66767b083ebd7a4c1565a 100644
--- a/lib/dom/dom.dart
+++ b/lib/dom/dom.dart
@@ -979,16 +979,6 @@ interface CanvasPattern {
 
 // WARNING: Do not edit - generated code.
 
-interface CanvasPixelArray extends List<int> {
-
-  final int length;
-}
-// 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.
-
-// WARNING: Do not edit - generated code.
-
 interface CanvasRenderingContext {
 
   final HTMLCanvasElement canvas;