Plumb GpuSwapBuffers completion from Mus GPU thread to WS thread

components/mus/surfaces/surfaces_context_provider.h

 // Copyright 2014 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_SURFACES_SURFACES_CONTEXT_PROVIDER_H_
 #define COMPONENTS_MUS_SURFACES_SURFACES_CONTEXT_PROVIDER_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/non_thread_safe.h"
 #include "cc/output/context_provider.h"
 #include "components/mus/gles2/command_buffer_local_client.h"
 #include "ui/gfx/native_widget_types.h"
+#include "ui/gl/gl_surface.h"
 
 namespace gpu {
 
 class TransferBuffer;
 
 namespace gles2 {
 class GLES2CmdHelper;
 class GLES2Implementation;
 }
 
@@ skipping 21 matching lines @@
   gpu::ContextSupport* ContextSupport() override;
   class GrContext* GrContext() override;
   void InvalidateGrContext(uint32_t state) override;
   Capabilities ContextCapabilities() override;
   void DeleteCachedResources() override {}
   void SetLostContextCallback(
       const LostContextCallback& lost_context_callback) override;
   void SetupLock() override;
   base::Lock* GetLock() override;
 
+  // SurfacesContextProvider API.
+  void SetSwapBuffersCompletionCallback(
+      gfx::GLSurface::SwapCompletionCallback callback);
+
  protected:
   friend class base::RefCountedThreadSafe<SurfacesContextProvider>;
   ~SurfacesContextProvider() override;
 
  private:
   // CommandBufferLocalClient:
   void UpdateVSyncParameters(int64_t timebase, int64_t interval) override;
   void DidLoseContext() override;
+  void GpuCompletedSwapBuffers(gfx::SwapResult result) override;
 
   // From GLES2Context:
   // Initialized in BindToCurrentThread.
   scoped_ptr<gpu::gles2::GLES2CmdHelper> gles2_helper_;
   scoped_ptr<gpu::TransferBuffer> transfer_buffer_;
   scoped_ptr<gpu::gles2::GLES2Implementation> implementation_;
 
   cc::ContextProvider::Capabilities capabilities_;
   LostContextCallback lost_context_callback_;
 
   SurfacesContextProviderDelegate* delegate_;
   gfx::AcceleratedWidget widget_;
   CommandBufferLocal* command_buffer_local_;
 
+  gfx::GLSurface::SwapCompletionCallback swap_buffers_completion_callback_;
+
   base::Lock context_lock_;
 
   DISALLOW_COPY_AND_ASSIGN(SurfacesContextProvider);
 };
 
 }  // namespace mus
 
 #endif  // COMPONENTS_MUS_SURFACES_SURFACES_CONTEXT_PROVIDER_H_