Perform glReadPixels with PBOs in the gpu, if PBOs are available.

gpu/command_buffer/service/gles2_cmd_decoder.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.
 
 // This file contains the GLES2Decoder class.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_
 
 #include <vector>
@@ skipping 197 matching lines @@
   virtual ErrorState* GetErrorState() = 0;
 
   // A callback for messages from the decoder.
   virtual void SetShaderCacheCallback(const ShaderCacheCallback& callback) = 0;
 
   // Sets the callback for waiting on a sync point. The callback returns the
   // scheduling status (i.e. true if the channel is still scheduled).
   virtual void SetWaitSyncPointCallback(
       const WaitSyncPointCallback& callback) = 0;
 
+  virtual void WaitForReadPixels(base::Closure callback) = 0;
   virtual uint32 GetTextureUploadCount() = 0;
   virtual base::TimeDelta GetTotalTextureUploadTime() = 0;
   virtual base::TimeDelta GetTotalProcessingCommandsTime() = 0;
   virtual void AddProcessingCommandsTime(base::TimeDelta) = 0;
 
   // Returns true if the context was just lost due to e.g. GL_ARB_robustness.
   virtual bool WasContextLost() = 0;
 
   // Lose this context.
   virtual void LoseContext(uint32 reset_status) = 0;
@@ skipping 13 matching lines @@
   bool debug_;
   bool log_commands_;
   static bool testing_force_is_angle_;
 
   DISALLOW_COPY_AND_ASSIGN(GLES2Decoder);
 };
 
 }  // namespace gles2
 }  // namespace gpu
 #endif  // GPU_COMMAND_BUFFER_SERVICE_GLES2_CMD_DECODER_H_