content: Cleanup class/struct forward declarations

content/renderer/renderer_webcolorchooser_impl.h

 // Copyright (c) 2012 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_RENDERER_RENDERER_WEBCOLORCHOOSER_IMPL_H_
 #define CONTENT_RENDERER_RENDERER_WEBCOLORCHOOSER_IMPL_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "content/public/common/color_suggestion.h"
 #include "content/public/renderer/render_frame_observer.h"
 #include "third_party/WebKit/public/web/WebColorChooser.h"
 #include "third_party/WebKit/public/web/WebColorChooserClient.h"
 #include "third_party/skia/include/core/SkColor.h"
 
-namespace blink {
-class WebFrame;
-}
-
 namespace content {
 
 class RendererWebColorChooserImpl : public blink::WebColorChooser,
                                     public RenderFrameObserver {
  public:
   explicit RendererWebColorChooserImpl(RenderFrame* render_frame,
                                        blink::WebColorChooserClient*);
   ~RendererWebColorChooserImpl() override;
 
   // blink::WebColorChooser implementation:
@@ skipping 18 matching lines @@
 
   int identifier_;
   blink::WebColorChooserClient* client_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererWebColorChooserImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDERER_WEBCOLORCHOOSER_IMPL_H_