content: Cleanup class/struct forward declarations

content/renderer/gpu/render_widget_compositor.h

 // Copyright (c) 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_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_H_
 #define CONTENT_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_H_
 
 #include <stdint.h>
 
 #include "base/callback.h"
@@ skipping 11 matching lines @@
 #include "content/common/content_export.h"
 #include "content/renderer/gpu/compositor_dependencies.h"
 #include "third_party/WebKit/public/platform/WebLayerTreeView.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace base {
 class CommandLine;
 }
 
 namespace cc {
-class CopyOutputRequest;
 class InputHandler;
 class Layer;
 class LayerTreeHost;
 namespace proto {
 class CompositorMessage;
 }
 }
 
 namespace gfx {
 class ColorSpace;
@@ skipping 187 matching lines @@
   blink::WebLayoutAndPaintAsyncCallback* layout_and_paint_async_callback_;
 
   cc::RemoteProtoChannel::ProtoReceiver* remote_proto_channel_receiver_;
 
   base::WeakPtrFactory<RenderWidgetCompositor> weak_factory_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_GPU_RENDER_WIDGET_COMPOSITOR_H_