Implement proper synchronization between HW video decode IPC and CommandBuffer.

gpu/command_buffer/service/gpu_scheduler.h

 // Copyright (c) 2011 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_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_H_
 
 #include <map>
 #include <queue>
 #include <vector>
@@ skipping 140 matching lines @@
 
   void SetCommandProcessedCallback(Callback0::Type* callback);
 
   // Sets a callback which is called after a Set/WaitLatch command is processed.
   // The bool parameter will be true for SetLatch, and false for a WaitLatch
   // that is blocked. An unblocked WaitLatch will not trigger a callback.
   void SetLatchCallback(const base::Callback<void(bool)>& callback) {
     decoder_->SetLatchCallback(callback);
   }
 
+  // Sets a callback which is called when set_token() is called, and passes the
+  // just-set token to the callback.  DCHECKs that no callback has previously
+  // been registered for this notification.
+  void SetTokenCallback(const base::Callback<void(int32)>& callback);
+
   // Get the GLES2Decoder associated with this scheduler.
   gles2::GLES2Decoder* decoder() const { return decoder_.get(); }
 
  protected:
   // Perform common initialization. Takes ownership of GLSurface and GLContext.
   bool InitializeCommon(
       const scoped_refptr<gfx::GLSurface>& surface,
       const scoped_refptr<gfx::GLContext>& context,
       const gfx::Size& size,
       const gles2::DisallowedExtensions& disallowed_extensions,
@@ skipping 40 matching lines @@
   std::map<uint64, scoped_refptr<AcceleratedSurface> >
       surfaces_;
   scoped_refptr<AcceleratedSurface> back_surface_;
   scoped_refptr<AcceleratedSurface> front_surface_;
 #endif
 
   ScopedRunnableMethodFactory<GpuScheduler> method_factory_;
   scoped_ptr<Callback1<gfx::Size>::Type> wrapped_resize_callback_;
   scoped_ptr<Callback0::Type> wrapped_swap_buffers_callback_;
   scoped_ptr<Callback0::Type> command_processed_callback_;
+  base::Callback<void(int32)> set_token_callback_;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GPU_SCHEDULER_H_