Merging dart:html interfaces and implementations

sdk/lib/html/templates/html/impl/impl_WebSocket.darttemplate

Index: sdk/lib/html/templates/html/impl/impl_WebSocket.darttemplate
diff --git a/sdk/lib/html/templates/html/dart2js/impl_CanvasElement.darttemplate b/sdk/lib/html/templates/html/impl/impl_WebSocket.darttemplate
similarity index 68%
copy from sdk/lib/html/templates/html/dart2js/impl_CanvasElement.darttemplate
copy to sdk/lib/html/templates/html/impl/impl_WebSocket.darttemplate
index 1c790c0afe67b39f424f3d8f972bc8965ef0bedd..2c2ef599e69b01bd9d80a4cd3b2a2a5147852777 100644
--- a/sdk/lib/html/templates/html/dart2js/impl_CanvasElement.darttemplate
+++ b/sdk/lib/html/templates/html/impl/impl_WebSocket.darttemplate
@@ -2,8 +2,9 @@
 // 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.
+
 class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
+  factory $CLASSNAME(String url) => _$(CLASSNAME)FactoryProvider.create$CLASSNAME(url);
 $!MEMBERS
-
-  _CanvasRenderingContext2DImpl get context2d => getContext('2d');
 }