viz: Convert a sync api in ServerGpuMemoryBufferManager into async.

components/viz/common/server_gpu_memory_buffer_manager.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_VIZ_COMMON_SERVER_GPU_MEMORY_BUFFER_MANAGER_H_
 #define COMPONENTS_VIZ_COMMON_SERVER_GPU_MEMORY_BUFFER_MANAGER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
-#include "base/threading/thread_checker.h"
+#include "base/sequenced_task_runner.h"
+#include "base/synchronization/waitable_event.h"
 #include "gpu/command_buffer/client/gpu_memory_buffer_manager.h"
 #include "gpu/ipc/host/gpu_memory_buffer_support.h"
 
 namespace ui {
 namespace mojom {
 class GpuService;
 }
 }
 
 namespace viz {
 
 // This GpuMemoryBufferManager implementation is for [de]allocating gpu memory
 // from the gpu process over the mojom.GpuService api.
-class ServerGpuMemoryBufferManager : public gpu::GpuMemoryBufferManager,
-                                     public base::ThreadChecker {
+// Note that |CreateGpuMemoryBuffer()| can be called on any thread. All the rest
+// of the functions must be called on the thread this object is created on.
+class ServerGpuMemoryBufferManager : public gpu::GpuMemoryBufferManager {
  public:
   ServerGpuMemoryBufferManager(ui::mojom::GpuService* gpu_service,
                                int client_id);
   ~ServerGpuMemoryBufferManager() override;
 
   void DestroyGpuMemoryBuffer(gfx::GpuMemoryBufferId id,
                               int client_id,
                               const gpu::SyncToken& sync_token);
 
   void DestroyAllGpuMemoryBufferForClient(int client_id);
 
-  gfx::GpuMemoryBufferHandle CreateGpuMemoryBufferHandle(
+  void AllocateGpuMemoryBuffer(
       gfx::GpuMemoryBufferId id,
       int client_id,
       const gfx::Size& size,
       gfx::BufferFormat format,
       gfx::BufferUsage usage,
-      gpu::SurfaceHandle surface_handle);
+      gpu::SurfaceHandle surface_handle,
+      base::OnceCallback<void(const gfx::GpuMemoryBufferHandle&)> callback);
 
   // Overridden from gpu::GpuMemoryBufferManager:
   std::unique_ptr<gfx::GpuMemoryBuffer> CreateGpuMemoryBuffer(
       const gfx::Size& size,
       gfx::BufferFormat format,
       gfx::BufferUsage usage,
       gpu::SurfaceHandle surface_handle) override;
   void SetDestructionSyncToken(gfx::GpuMemoryBuffer* buffer,
                                const gpu::SyncToken& sync_token) override;
 
  private:
+  void OnGpuMemoryBufferAllocated(
+      int client_id,
+      base::OnceCallback<void(const gfx::GpuMemoryBufferHandle&)> callback,
+      const gfx::GpuMemoryBufferHandle& handle);
+
   ui::mojom::GpuService* gpu_service_;
   const int client_id_;
   int next_gpu_memory_id_ = 1;
 
   using NativeBuffers =
       std::unordered_set<gfx::GpuMemoryBufferId,
                          BASE_HASH_NAMESPACE::hash<gfx::GpuMemoryBufferId>>;
   std::unordered_map<int, NativeBuffers> native_buffers_;
+  std::unordered_set<int> pending_buffers_;
 
   const gpu::GpuMemoryBufferConfigurationSet native_configurations_;
+  scoped_refptr<base::SequencedTaskRunner> task_runner_;
   base::WeakPtrFactory<ServerGpuMemoryBufferManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServerGpuMemoryBufferManager);
 };
 
 }  // namespace viz
 
 #endif  // COMPONENTS_VIZ_COMMON_SERVER_GPU_MEMORY_BUFFER_MANAGER_H_