Add OrderingBarrierCHROMIUM API.

gpu/command_buffer/common/command_buffer.h

 // Copyright (c) 2012 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_COMMON_COMMAND_BUFFER_H_
 #define GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_
 
 #include "gpu/command_buffer/common/buffer.h"
 #include "gpu/command_buffer/common/constants.h"
 #include "gpu/gpu_export.h"
@@ skipping 72 matching lines @@
   // by code that needs to know the last token so it can be slower but more up
   // to date than GetLastState.
   virtual int32 GetLastToken() = 0;
 
   // The writer calls this to update its put offset. This ensures the reader
   // sees the latest added commands, and will eventually process them. On the
   // service side, commands are processed up to the given put_offset before
   // subsequent Flushes on the same GpuChannel.
   virtual void Flush(int32 put_offset) = 0;
 
+  // As Flush, ensures that on the service side, commands up to put_offset
+  // are processed but before subsequent commands on the same GpuChannel but
+  // flushing to the service may be deferred.
+  virtual void OrderingBarrier(int32 put_offset) = 0;
+
   // The writer calls this to wait until the current token is within a
   // specific range, inclusive. Can return early if an error is generated.
   virtual void WaitForTokenInRange(int32 start, int32 end) = 0;
 
   // The writer calls this to wait until the current get offset is within a
   // specific range, inclusive. Can return early if an error is generated.
   virtual void WaitForGetOffsetInRange(int32 start, int32 end) = 0;
 
   // Sets the buffer commands are read from.
   // Also resets the get and put offsets to 0.
@@ skipping 18 matching lines @@
   virtual error::Error GetLastError();
 #endif
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CommandBuffer);
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_COMMON_COMMAND_BUFFER_H_