ui: Add libsync GLFence implementation.

gpu/ipc/client/gpu_fence_impl.h

Index: gpu/ipc/client/gpu_fence_impl.h
diff --git a/gpu/ipc/client/gpu_fence_impl.h b/gpu/ipc/client/gpu_fence_impl.h
index 1c82d014981839e369ce567cd8979e4f6472813f..1ee1b62864061b255cd5ec722bd8d63cfa2e6f32 100644
--- a/gpu/ipc/client/gpu_fence_impl.h
+++ b/gpu/ipc/client/gpu_fence_impl.h
@@ -7,7 +7,6 @@
 
 #include "gpu/gpu_export.h"
 #include "ui/gfx/gpu_fence.h"
-#include "ui/gfx/shared_event.h"
 
 namespace gpu {
 
@@ -15,12 +14,14 @@ namespace gpu {
 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);
 
@@ -28,12 +29,9 @@ class GPU_EXPORT GpuFenceImpl : public 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);
 };