Remove unused forward decls from render_frame.h

content/public/renderer/render_frame.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_RENDERER_RENDER_FRAME_H_
 #define CONTENT_PUBLIC_RENDERER_RENDER_FRAME_H_
 
 #include <stddef.h>
 
 #include <memory>
 
 #include "base/callback_forward.h"
 #include "base/strings/string16.h"
 #include "content/common/content_export.h"
 #include "content/public/common/console_message_level.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_sender.h"
 #include "third_party/WebKit/public/web/WebNavigationPolicy.h"
 
 class GURL;
 
 namespace blink {
-class WebElement;
 class WebFrame;
 class WebLocalFrame;
-class WebNode;
 class WebPlugin;
 class WebURLRequest;
 class WebURLResponse;
 struct WebPluginParams;
 }
 
 namespace gfx {
 class Range;
 class Size;
 }
@@ skipping 171 matching lines @@
 
  private:
   // This interface should only be implemented inside content.
   friend class RenderFrameImpl;
   RenderFrame() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_RENDERER_RENDER_FRAME_H_