Add dummy dart:html library for documentation.

lib/html/doc/interface/Entry.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 Entry
+interface Entry {
+
+  /** @domName Entry.filesystem */
+  final DOMFileSystem filesystem;
+
+  /** @domName Entry.fullPath */
+  final String fullPath;
+
+  /** @domName Entry.isDirectory */
+  final bool isDirectory;
+
+  /** @domName Entry.isFile */
+  final bool isFile;
+
+  /** @domName Entry.name */
+  final String name;
+
+  /** @domName Entry.copyTo */
+  void copyTo(DirectoryEntry parent, [String name, EntryCallback successCallback, ErrorCallback errorCallback]);
+
+  /** @domName Entry.getMetadata */
+  void getMetadata(MetadataCallback successCallback, [ErrorCallback errorCallback]);
+
+  /** @domName Entry.getParent */
+  void getParent([EntryCallback successCallback, ErrorCallback errorCallback]);
+
+  /** @domName Entry.moveTo */
+  void moveTo(DirectoryEntry parent, [String name, EntryCallback successCallback, ErrorCallback errorCallback]);
+
+  /** @domName Entry.remove */
+  void remove(VoidCallback successCallback, [ErrorCallback errorCallback]);
+
+  /** @domName Entry.toURL */
+  String toURL();
+}