Remove explicit interface versions of dartdoc files.

lib/html/doc/interface/EventSource.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 EventSource
-interface EventSource extends EventTarget default _EventSourceFactoryProvider {
-
-  EventSource(String scriptUrl);
-
-  /**
-   * @domName EventTarget.addEventListener, EventTarget.removeEventListener, EventTarget.dispatchEvent
-   */
-  EventSourceEvents get on();
-
-  static final int CLOSED = 2;
-
-  static final int CONNECTING = 0;
-
-  static final int OPEN = 1;
-
-  /** @domName EventSource.URL */
-  final String URL;
-
-  /** @domName EventSource.readyState */
-  final int readyState;
-
-  /** @domName EventSource.url */
-  final String url;
-
-  /** @domName EventSource.addEventListener */
-  void $dom_addEventListener(String type, EventListener listener, [bool useCapture]);
-
-  /** @domName EventSource.close */
-  void close();
-
-  /** @domName EventSource.dispatchEvent */
-  bool $dom_dispatchEvent(Event evt);
-
-  /** @domName EventSource.removeEventListener */
-  void $dom_removeEventListener(String type, EventListener listener, [bool useCapture]);
-}
-
-interface EventSourceEvents extends Events {
-
-  EventListenerList get error();
-
-  EventListenerList get message();
-
-  EventListenerList get open();
-}