Removing the dependency of command-buffer client on base/task.h. This file in...

gpu/command_buffer/service/command_buffer_service.h

 // Copyright (c) 2009 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_COMMAND_BUFFER_SERVICE_H_
 #define GPU_COMMAND_BUFFER_SERVICE_COMMAND_BUFFER_SERVICE_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 13 matching lines @@
   virtual ~CommandBufferService();
 
   // CommandBuffer implementation:
   virtual bool Initialize(int32 size);
   virtual Buffer GetRingBuffer();
   virtual int32 GetSize();
   virtual int32 SyncOffsets(int32 put_offset);
   virtual int32 GetGetOffset();
   virtual void SetGetOffset(int32 get_offset);
   virtual int32 GetPutOffset();
-  virtual void SetPutOffsetChangeCallback(Callback0::Type* callback);
   virtual int32 CreateTransferBuffer(size_t size);
   virtual void DestroyTransferBuffer(int32 id);
   virtual Buffer GetTransferBuffer(int32 handle);
   virtual int32 GetToken();
   virtual void SetToken(int32 token);
   virtual int32 ResetParseError();
   virtual void SetParseError(int32 parse_error);
   virtual bool GetErrorStatus();
   virtual void RaiseErrorStatus();
 
+  // Sets a callback that should be posted on another thread whenever the put
+  // offset is changed. The callback must not return until some progress has
+  // been made (unless the command buffer is empty), i.e. the
+  // get offset must have changed. It need not process the entire command
+  // buffer though. This allows concurrency between the writer and the reader
+  // while giving the writer a means of waiting for the reader to make some
+  // progress before attempting to write more to the command buffer. Avoiding
+  // the use of a synchronization primitive like a condition variable to
+  // synchronize reader and writer reduces the risk of deadlock.
+  // Takes ownership of callback. The callback is invoked on the plugin thread.
+  virtual void SetPutOffsetChangeCallback(Callback0::Type* callback);
+
  private:
   scoped_ptr< base::SharedMemory> ring_buffer_;
   int32 size_;
   int32 get_offset_;
   int32 put_offset_;
   scoped_ptr<Callback0::Type> put_offset_change_callback_;
   std::vector<linked_ptr< base::SharedMemory> > registered_objects_;
   std::set<int32> unused_registered_object_elements_;
   int32 token_;
   int32 parse_error_;
   bool error_status_;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_COMMAND_BUFFER_SERVICE_H_