gpu: Notify callbacks the reason for channel creation failure

content/browser/gpu/browser_gpu_channel_host_factory.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_BROWSER_GPU_BROWSER_GPU_CHANNEL_HOST_FACTORY_H_
 #define CONTENT_BROWSER_GPU_BROWSER_GPU_CHANNEL_HOST_FACTORY_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 18 matching lines @@
   static void Initialize(bool establish_gpu_channel);
   static void Terminate();
   static BrowserGpuChannelHostFactory* instance() { return instance_; }
 
   // Overridden from gpu::GpuChannelHostFactory:
   bool IsMainThread() override;
   scoped_refptr<base::SingleThreadTaskRunner> GetIOThreadTaskRunner() override;
   std::unique_ptr<base::SharedMemory> AllocateSharedMemory(
       size_t size) override;
 
-  int GpuProcessHostId() { return gpu_host_id_; }
   gpu::GpuChannelHost* GetGpuChannel();
   int GetGpuChannelId() { return gpu_client_id_; }
 
   // Closes the channel to the GPU process. This should be called before the IO
   // thread stops.
   void CloseChannel();
 
   // Used to skip GpuChannelHost tests when there can be no GPU process.
   static bool CanUseForTesting();
 
@@ skipping 15 matching lines @@
   void GpuChannelEstablished();
 
   static void InitializeShaderDiskCacheOnIO(int gpu_client_id,
                                             const base::FilePath& cache_dir);
 
   const int gpu_client_id_;
   const uint64_t gpu_client_tracing_id_;
   std::unique_ptr<base::WaitableEvent> shutdown_event_;
   scoped_refptr<gpu::GpuChannelHost> gpu_channel_;
   std::unique_ptr<BrowserGpuMemoryBufferManager> gpu_memory_buffer_manager_;
-  int gpu_host_id_;
   scoped_refptr<EstablishRequest> pending_request_;
   std::vector<gpu::GpuChannelEstablishedCallback> established_callbacks_;
 
   static BrowserGpuChannelHostFactory* instance_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserGpuChannelHostFactory);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_BROWSER_GPU_CHANNEL_HOST_FACTORY_H_