Add dummy dart:html library for documentation.

lib/html/doc/interface/DOMApplicationCache.dartdoc

+// 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:
+//   This file contains documentation that is merged into the real source.
+//   Do not make code changes here.
+
+/// @domName DOMApplicationCache
+interface DOMApplicationCache extends EventTarget {
+
+  /**
+   * @domName EventTarget.addEventListener, EventTarget.removeEventListener, EventTarget.dispatchEvent
+   */
+  DOMApplicationCacheEvents get on();
+
+  static final int CHECKING = 2;
+
+  static final int DOWNLOADING = 3;
+
+  static final int IDLE = 1;
+
+  static final int OBSOLETE = 5;
+
+  static final int UNCACHED = 0;
+
+  static final int UPDATEREADY = 4;
+
+  /** @domName DOMApplicationCache.status */
+  final int status;
+
+  /** @domName DOMApplicationCache.abort */
+  void abort();
+
+  /** @domName DOMApplicationCache.addEventListener */
+  void $dom_addEventListener(String type, EventListener listener, [bool useCapture]);
+
+  /** @domName DOMApplicationCache.dispatchEvent */
+  bool $dom_dispatchEvent(Event evt);
+
+  /** @domName DOMApplicationCache.removeEventListener */
+  void $dom_removeEventListener(String type, EventListener listener, [bool useCapture]);
+
+  /** @domName DOMApplicationCache.swapCache */
+  void swapCache();
+
+  /** @domName DOMApplicationCache.update */
+  void update();
+}
+
+interface DOMApplicationCacheEvents extends Events {
+
+  EventListenerList get cached();
+
+  EventListenerList get checking();
+
+  EventListenerList get downloading();
+
+  EventListenerList get error();
+
+  EventListenerList get noUpdate();
+
+  EventListenerList get obsolete();
+
+  EventListenerList get progress();
+
+  EventListenerList get updateReady();
+}