blimp: Cleanup class/struct forward declarations

blimp/client/support/compositor/compositor_dependencies_impl.h

 // Copyright 2016 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 BLIMP_CLIENT_SUPPORT_COMPOSITOR_COMPOSITOR_DEPENDENCIES_IMPL_H_
 #define BLIMP_CLIENT_SUPPORT_COMPOSITOR_COMPOSITOR_DEPENDENCIES_IMPL_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "blimp/client/public/compositor/compositor_dependencies.h"
 
-namespace cc {
-class ContextProvider;
-}
-
 namespace blimp {
 namespace client {
 
 class BlimpGpuMemoryBufferManager;
 
 class CompositorDependenciesImpl : public CompositorDependencies {
  public:
   CompositorDependenciesImpl();
   ~CompositorDependenciesImpl() override;
 
   // CompositorDependencies implementation.
   gpu::GpuMemoryBufferManager* GetGpuMemoryBufferManager() override;
   cc::SurfaceManager* GetSurfaceManager() override;
   cc::FrameSinkId AllocateFrameSinkId() override;
   void GetContextProviders(const ContextProviderCallback& callback) override;
 
  private:
   std::unique_ptr<BlimpGpuMemoryBufferManager> gpu_memory_buffer_manager_;
   std::unique_ptr<cc::SurfaceManager> surface_manager_;
   uint32_t next_surface_id_;
 
   DISALLOW_COPY_AND_ASSIGN(CompositorDependenciesImpl);
 };
 
 }  // namespace client
 }  // namespace blimp
 
 #endif  // BLIMP_CLIENT_SUPPORT_COMPOSITOR_COMPOSITOR_DEPENDENCIES_IMPL_H_