content: Cleanup class/struct forward declarations

content/browser/compositor/gpu_browser_compositor_output_surface.h

 // Copyright 2014 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_BROWSER_COMPOSITOR_GPU_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 #define CONTENT_BROWSER_COMPOSITOR_GPU_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "build/build_config.h"
 #include "content/browser/compositor/browser_compositor_output_surface.h"
 #include "ui/gfx/swap_result.h"
 
 namespace display_compositor {
 class CompositorOverlayCandidateValidator;
 }
 
 namespace gpu {
 class CommandBufferProxyImpl;
+struct GpuProcessHostedCALayerTreeParamsMac;
 }
 
 namespace ui {
 class CompositorVSyncManager;
 }
 
 namespace content {
+class ContextProviderCommandBuffer;
 class ReflectorTexture;
 
 // Adapts a WebGraphicsContext3DCommandBufferImpl into a
 // cc::OutputSurface that also handles vsync parameter updates
 // arriving from the GPU process.
 class GpuBrowserCompositorOutputSurface
     : public BrowserCompositorOutputSurface {
  public:
   GpuBrowserCompositorOutputSurface(
       scoped_refptr<ContextProviderCommandBuffer> context,
@@ skipping 42 matching lines @@
   std::unique_ptr<ReflectorTexture> reflector_texture_;
   base::WeakPtrFactory<GpuBrowserCompositorOutputSurface> weak_ptr_factory_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(GpuBrowserCompositorOutputSurface);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_COMPOSITOR_GPU_BROWSER_COMPOSITOR_OUTPUT_SURFACE_H_