Add dummy dart:html library for documentation.

lib/html/doc/interface/FileEntry.dart

Index: lib/html/doc/interface/FileEntry.dart
diff --git a/lib/html/doc/interface/FileEntry.dart b/lib/html/doc/interface/FileEntry.dart
new file mode 100644
index 0000000000000000000000000000000000000000..74d3aec2be113ae1d702ebdd7100bb3e8c41746f
--- /dev/null
+++ b/lib/html/doc/interface/FileEntry.dart
@@ -0,0 +1,15 @@
+// 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: Do not edit - generated code.
+
+/// @domName FileEntry
+interface FileEntry extends Entry {
+
+  /** @domName FileEntry.createWriter */
+  void createWriter(FileWriterCallback successCallback, [ErrorCallback errorCallback]);
+
+  /** @domName FileEntry.file */
+  void file(FileCallback successCallback, [ErrorCallback errorCallback]);
+}