ui: Add libsync GLFence implementation.

gpu/ipc/client/gpu_fence_impl.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 GPU_IPC_CLIENT_GPU_FENCE_IMPL_H_
 #define GPU_IPC_CLIENT_GPU_FENCE_IMPL_H_
 
 #include "gpu/gpu_export.h"
 #include "ui/gfx/gpu_fence.h"
-#include "ui/gfx/shared_event.h"
 
 namespace gpu {
 
 // Provides common implementation of a GPU fence.
 class GPU_EXPORT GpuFenceImpl : public gfx::GpuFence {
  public:
   GpuFenceImpl();
-  explicit GpuFenceImpl(const gfx::GpuFenceHandle& handle);
   ~GpuFenceImpl() override;
 
   static gfx::GpuFenceHandle CreateForChildProcess(
       base::ProcessHandle child_process);
 
+  static std::unique_ptr<GpuFenceImpl> CreateFromHandle(
+      const gfx::GpuFenceHandle& handle);
+
   // Type-checking upcast routine. Returns an NULL on failure.
   static GpuFenceImpl* FromClientFence(ClientFence fence);
 
   // Overridden from gfx::GpuFence:
   bool IsSignaled() override;
   bool Wait(const base::TimeDelta& max_time) override;
   void Reset() override;
-  gfx::GpuFenceHandle GetHandle() const override;
   ClientFence AsClientFence() override;
 
  private:
-  gfx::SharedEvent shared_event_;
-
   DISALLOW_COPY_AND_ASSIGN(GpuFenceImpl);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_IPC_CLIENT_GPU_FENCE_IMPL_H_