Implement proper synchronization between HW video decode IPC and CommandBuffer.

content/common/gpu/gpu_command_buffer_stub.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 CONTENT_COMMON_GPU_GPU_COMMAND_BUFFER_STUB_H_
 #define CONTENT_COMMON_GPU_GPU_COMMAND_BUFFER_STUB_H_
 #pragma once
 
 #if defined(ENABLE_GPU)
 
@@ skipping 45 matching lines @@
   // Identifies the renderer process.
   int32 renderer_id() const { return renderer_id_; }
 
   // Identifies a particular renderer belonging to the same renderer process.
   int32 render_view_id() const { return render_view_id_; }
 
   // Identifies the various GpuCommandBufferStubs in the GPU process belonging
   // to the same renderer process.
   int32 route_id() const { return route_id_; }
 
+  // Return the current token in the underlying command buffer, or 0 if not yet
+  // initialized.
+  int32 token() const {
+    return command_buffer_.get() ? command_buffer_->GetState().token : 0;
+  }
+
 #if defined(OS_WIN)
   // Called only by the compositor window's window proc
   void OnCompositorWindowPainted();
 #endif  // defined(OS_WIN)
 
   void ViewResized();
 
 #if defined(TOUCH_UI)
   void AcceleratedSurfaceIOSurfaceSet(uint64 surface_id);
   void AcceleratedSurfaceReleased(uint64 surface_id);
 #endif  // defined(TOUCH_UI)
 
 #if defined(OS_MACOSX) || defined(TOUCH_UI)
   // Called only by the GpuChannel.
   void AcceleratedSurfaceBuffersSwapped(uint64 swap_buffers_count);
 #endif  // defined(OS_MACOSX) || defined(TOUCH_UI)
 
   // Called when the command buffer was destroyed, and the stub should now
   // unblock itself and handle pending messages.
   void CommandBufferWasDestroyed();
 
+  // Register a callback to be Run() whenever the underlying scheduler receives
+  // a set_token() call.  The callback will be Run() with the just-set token as
+  // its only parameter.  Multiple callbacks may be registered.
+  void AddSetTokenCallback(const base::Callback<void(int32)>& callback);
+
  private:
   // Message handlers:
   void OnInitialize(base::SharedMemoryHandle ring_buffer,
                     int32 size,
                     IPC::Message* reply_message);
   void OnSetParent(int32 parent_route_id,
                    uint32 parent_texture_id,
                    IPC::Message* reply_message);
   void OnGetState(IPC::Message* reply_message);
   void OnFlush(int32 put_offset,
@@ skipping 22 matching lines @@
   void OnSetWindowSize(const gfx::Size& size);
 #endif  // defined(OS_MACOSX)
 
 #if defined(OS_MACOSX) || defined(TOUCH_UI)
   void SwapBuffersCallback();
 #endif  // defined(TOUCH_UI)
 
   void ResizeCallback(gfx::Size size);
   void ReportState();
 
+  // Callback registered with GpuScheduler to receive set_token() notifications.
+  void OnSetToken(int32 token);
+
   // The lifetime of objects of this class is managed by a GpuChannel. The
   // GpuChannels destroy all the GpuCommandBufferStubs that they own when they
   // are destroyed. So a raw pointer is safe.
   GpuChannel* channel_;
 
   gfx::PluginWindowHandle handle_;
   gfx::Size initial_size_;
   gpu::gles2::DisallowedExtensions disallowed_extensions_;
   std::string allowed_extensions_;
   std::vector<int32> requested_attribs_;
   int32 route_id_;
   uint32 last_flush_count_;
 
   // The following two fields are used on Mac OS X to identify the window
   // for the rendering results on the browser side.
   int32 renderer_id_;
   int32 render_view_id_;
 
   scoped_ptr<gpu::CommandBufferService> command_buffer_;
   scoped_ptr<gpu::GpuScheduler> scheduler_;
   std::queue<IPC::Message*> deferred_messages_;
+  std::vector<base::Callback<void(int32)> > set_token_callbacks_;
 
   // SetParent may be called before Initialize, in which case we need to keep
   // around the parent stub, so that Initialize can set the parent correctly.
   base::WeakPtr<GpuCommandBufferStub> parent_stub_for_initialization_;
   uint32 parent_texture_for_initialization_;
 
   GpuWatchdog* watchdog_;
   ScopedRunnableMethodFactory<GpuCommandBufferStub> task_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuCommandBufferStub);
 };
 
 #endif  // defined(ENABLE_GPU)
 
 #endif  // CONTENT_COMMON_GPU_GPU_COMMAND_BUFFER_STUB_H_