mus::GpuService: Support establish GpuChannel asynchronously.

components/mus/common/gpu_service.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 COMPONENTS_MUS_COMMON_GPU_SERVICE_H_
 #define COMPONENTS_MUS_COMMON_GPU_SERVICE_H_
 
 #include <stdint.h>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
+#include "components/mus/common/mojo_gpu_memory_buffer_manager.h"
 #include "components/mus/common/mus_common_export.h"
+#include "components/mus/public/interfaces/gpu_service.mojom.h"
 #include "gpu/ipc/client/gpu_channel_host.h"
 
 namespace shell {
 class Connector;
 }
 
 namespace mus {
 
-class MojoGpuMemoryBufferManager;
-
 class MUS_COMMON_EXPORT GpuService : public gpu::GpuChannelHostFactory {
  public:
-  scoped_refptr<gpu::GpuChannelHost> EstablishGpuChannel(
-      shell::Connector* connector);
+  void EstablishGpuChannel(const base::Closure& callback);
+  scoped_refptr<gpu::GpuChannelHost> EstablishGpuChannelSync();
+  scoped_refptr<gpu::GpuChannelHost> GetGpuChannel();
+  gpu::GpuMemoryBufferManager* gpu_memory_buffer_manager() const {
+    return gpu_memory_buffer_manager_.get();
+  }
 
   static bool UseChromeGpuCommandBuffer();
+
+  // The GpuService has to be initialized in the main thread before establishing
+  // the gpu channel.
+  static void Initialize(shell::Connector* connector);
   static GpuService* GetInstance();
 
  private:
   friend struct base::DefaultSingletonTraits<GpuService>;
 
-  GpuService();
+  explicit GpuService(shell::Connector* connector);
   ~GpuService() override;
 
+  scoped_refptr<gpu::GpuChannelHost> GetGpuChannelLocked();
+  void EstablishGpuChannelOnMainThread();
+  void EstablishGpuChannelOnMainThreadLocked();
+  void EstablishGpuChannelOnMainThreadDone(
+      int client_id,
+      mojom::ChannelHandlePtr channel_handle,
+      mojom::GpuInfoPtr gpu_info);
+
   // gpu::GpuChannelHostFactory overrides:
   bool IsMainThread() override;
   scoped_refptr<base::SingleThreadTaskRunner> GetIOThreadTaskRunner() override;
   std::unique_ptr<base::SharedMemory> AllocateSharedMemory(
       size_t size) override;
 
   base::MessageLoop* main_message_loop_;
+  shell::Connector* connector_;
   base::WaitableEvent shutdown_event_;
   base::Thread io_thread_;
   std::unique_ptr<MojoGpuMemoryBufferManager> gpu_memory_buffer_manager_;
 
-  // Lock for |gpu_channel_|.
+  // Lock for |gpu_channel_|, |establish_callbacks_| & |is_establishing_|.
   base::Lock lock_;
+  bool is_establishing_;
+  mus::mojom::GpuServicePtr gpu_service_;
   scoped_refptr<gpu::GpuChannelHost> gpu_channel_;
+  std::vector<base::Closure> establish_callbacks_;
+  base::ConditionVariable establishing_condition_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuService);
 };
 
 }  // namespace mus
 
 #endif  // COMPONENTS_MUS_PUBLIC_CPP_LIB_GPU_SERVICE_CONNECTION_H_