Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/VideoElement.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 HTMLVideoElement
-interface VideoElement extends MediaElement default _Elements {
-
-  VideoElement();
-
-  /** @domName HTMLVideoElement.height */
-  int height;
-
-  /** @domName HTMLVideoElement.poster */
-  String poster;
-
-  /** @domName HTMLVideoElement.videoHeight */
-  final int videoHeight;
-
-  /** @domName HTMLVideoElement.videoWidth */
-  final int videoWidth;
-
-  /** @domName HTMLVideoElement.webkitDecodedFrameCount */
-  final int webkitDecodedFrameCount;
-
-  /** @domName HTMLVideoElement.webkitDisplayingFullscreen */
-  final bool webkitDisplayingFullscreen;
-
-  /** @domName HTMLVideoElement.webkitDroppedFrameCount */
-  final int webkitDroppedFrameCount;
-
-  /** @domName HTMLVideoElement.webkitSupportsFullscreen */
-  final bool webkitSupportsFullscreen;
-
-  /** @domName HTMLVideoElement.width */
-  int width;
-
-  /** @domName HTMLVideoElement.webkitEnterFullScreen */
-  void webkitEnterFullScreen();
-
-  /** @domName HTMLVideoElement.webkitEnterFullscreen */
-  void webkitEnterFullscreen();
-
-  /** @domName HTMLVideoElement.webkitExitFullScreen */
-  void webkitExitFullScreen();
-
-  /** @domName HTMLVideoElement.webkitExitFullscreen */
-  void webkitExitFullscreen();
-}