Changing template file names to key off of the DOM name rather than Dart name.

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

Index: sdk/lib/html/templates/html/impl/impl_CanvasElement.darttemplate
diff --git a/sdk/lib/html/templates/html/impl/impl_CanvasElement.darttemplate b/sdk/lib/html/templates/html/impl/impl_CanvasElement.darttemplate
deleted file mode 100644
index cb5aa2a34d1d399388e5a793539e8cd98bd2d49b..0000000000000000000000000000000000000000
--- a/sdk/lib/html/templates/html/impl/impl_CanvasElement.darttemplate
+++ /dev/null
@@ -1,15 +0,0 @@
-// 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.
-
-part of html;
-
-/// @domName $DOMNAME
-class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
-$!MEMBERS
-
-$if DART2JS
-  CanvasRenderingContext getContext(String contextId) native;
-$endif
-  CanvasRenderingContext2D get context2d => getContext('2d');
-}