Adding 'part of html' to all files which are used by dart:html.

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

Index: sdk/lib/html/templates/html/impl/pure_interface.darttemplate
diff --git a/sdk/lib/html/templates/html/impl/pure_interface.darttemplate b/sdk/lib/html/templates/html/impl/pure_interface.darttemplate
index 5f0e58c5b323bcb15bf10a8ec9879bf5e5ddcf43..71f22dbc7ff49f10ba49cc87830ec2067aed795b 100644
--- a/sdk/lib/html/templates/html/impl/pure_interface.darttemplate
+++ b/sdk/lib/html/templates/html/impl/pure_interface.darttemplate
@@ -1,3 +1,9 @@
+// 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
 abstract class $CLASSNAME$EXTENDS$IMPLEMENTS {
 $!MEMBERS}