Changed GpuVSyncProvider to implement gfx::VSyncProvider

gpu/ipc/service/gpu_vsync_provider.h

-// Copyright (c) 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 GPU_IPC_SERVICE_GPU_VSYNC_PROVIDER_H_
-#define GPU_IPC_SERVICE_GPU_VSYNC_PROVIDER_H_
-
-#include <memory>
-
-#include "base/callback.h"
-#include "base/time/time.h"
-#include "gpu/gpu_export.h"
-#include "gpu/ipc/common/surface_handle.h"
-
-namespace gpu {
-
-class GpuVSyncWorker;
-
-// Implements waiting for VSync signal on background thread.
-class GPU_EXPORT GpuVSyncProvider {
- public:
-  // Once VSync is enabled, this callback is repeatedly invoked on every VSync.
-  // The call is made on background thread to avoid increased latency due to
-  // serializing callback invocation with other GPU tasks. The code that
-  // implements the callback function is expected to handle that.
-  using VSyncCallback = base::Callback<void(base::TimeTicks timestamp)>;
-
-  ~GpuVSyncProvider();
-
-  static std::unique_ptr<GpuVSyncProvider> Create(const VSyncCallback& callback,
-                                                  SurfaceHandle surface_handle);
-
-  // Enable or disable VSync production.
-  void EnableVSync(bool enabled);
-
- private:
-#if defined(OS_WIN)
-  GpuVSyncProvider(const VSyncCallback& callback, SurfaceHandle surface_handle);
-
-  std::unique_ptr<GpuVSyncWorker> vsync_worker_;
-#endif  // defined(OS_WIN)
-
-  DISALLOW_COPY_AND_ASSIGN(GpuVSyncProvider);
-};
-
-}  // namespace gpu
-
-#endif  // GPU_IPC_SERVICE_GPU_VSYNC_PROVIDER_H_