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

sdk/lib/html/src/KeyName.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.
 
+part of html;
+
 /**
  * Defines the standard keyboard identifier names for keys that are returned
  * by KeyEvent.getKeyboardIdentifier when the key does not have a direct
  * unicode mapping.
  */
 abstract class KeyName {
 
   /** The Accept (Commit, OK) key */
   static const String ACCEPT = "Accept";
 
@@ skipping 469 matching lines @@
    * Sound) key
    */
   static const String DEC_SEMIVOICED_SOUND= "DeadSemivoicedSound";
 
   /**
    * Key value used when an implementation is unable to identify another key
    * value, due to either hardware, platform, or software constraints
    */
   static const String UNIDENTIFIED = "Unidentified";
 }