Add dummy dart:html library for documentation.

lib/html/doc/interface/FileReader.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 FileReader
+interface FileReader extends EventTarget default _FileReaderFactoryProvider {
+
+  FileReader();
+
+  /**
+   * @domName EventTarget.addEventListener, EventTarget.removeEventListener, EventTarget.dispatchEvent
+   */
+  FileReaderEvents get on();
+
+  static final int DONE = 2;
+
+  static final int EMPTY = 0;
+
+  static final int LOADING = 1;
+
+  /** @domName FileReader.error */
+  final FileError error;
+
+  /** @domName FileReader.readyState */
+  final int readyState;
+
+  /** @domName FileReader.result */
+  final Object result;
+
+  /** @domName FileReader.abort */
+  void abort();
+
+  /** @domName FileReader.addEventListener */
+  void $dom_addEventListener(String type, EventListener listener, [bool useCapture]);
+
+  /** @domName FileReader.dispatchEvent */
+  bool $dom_dispatchEvent(Event evt);
+
+  /** @domName FileReader.readAsArrayBuffer */
+  void readAsArrayBuffer(Blob blob);
+
+  /** @domName FileReader.readAsBinaryString */
+  void readAsBinaryString(Blob blob);
+
+  /** @domName FileReader.readAsDataURL */
+  void readAsDataURL(Blob blob);
+
+  /** @domName FileReader.readAsText */
+  void readAsText(Blob blob, [String encoding]);
+
+  /** @domName FileReader.removeEventListener */
+  void $dom_removeEventListener(String type, EventListener listener, [bool useCapture]);
+}
+
+interface FileReaderEvents extends Events {
+
+  EventListenerList get abort();
+
+  EventListenerList get error();
+
+  EventListenerList get load();
+
+  EventListenerList get loadEnd();
+
+  EventListenerList get loadStart();
+
+  EventListenerList get progress();
+}