content: Cleanup class/struct forward declarations

content/common/gpu/client/context_provider_command_buffer.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_COMMON_GPU_CLIENT_CONTEXT_PROVIDER_COMMAND_BUFFER_H_
 #define CONTENT_COMMON_GPU_CLIENT_CONTEXT_PROVIDER_COMMAND_BUFFER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 23 matching lines @@
 class GLES2Implementation;
 class GLES2TraceImplementation;
 }
 }
 
 namespace skia_bindings {
 class GrContextForGLES2Interface;
 }
 
 namespace content {
-class WebGraphicsContext3DCommandBufferImpl;
 
 // Implementation of cc::ContextProvider that provides a GL implementation over
 // command buffer to the GPU process.
 class CONTENT_EXPORT ContextProviderCommandBuffer
     : NON_EXPORTED_BASE(public cc::ContextProvider),
       public base::trace_event::MemoryDumpProvider {
  public:
   ContextProviderCommandBuffer(
       scoped_refptr<gpu::GpuChannelHost> channel,
       int32_t stream_id,
@@ skipping 80 matching lines @@
   std::unique_ptr<gpu::gles2::GLES2TraceImplementation> trace_impl_;
   std::unique_ptr<skia_bindings::GrContextForGLES2Interface> gr_context_;
   std::unique_ptr<cc::ContextCacheController> cache_controller_;
 
   LostContextCallback lost_context_callback_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_CONTEXT_PROVIDER_COMMAND_BUFFER_H_