GPUProcessor uses O3D command buffer service to render to a window....

o3d/command_buffer/service/cross/gapi_decoder.h

Index: o3d/command_buffer/service/cross/gapi_decoder.h
===================================================================
--- o3d/command_buffer/service/cross/gapi_decoder.h	(revision 26805)
+++ o3d/command_buffer/service/cross/gapi_decoder.h	(working copy)
@@ -42,7 +42,7 @@
 namespace command_buffer {
 
 class GAPIInterface;
-class CommandBufferEngine;
+class CommandBufferUpcallInterface;
 
 // This class implements the AsyncAPIInterface interface, decoding GAPI
 // commands and sending them to a GAPI interface.
@@ -66,7 +66,7 @@
 
   // Sets the engine, to get shared memory buffers from, and to set the token
   // to.
-  void set_engine(CommandBufferEngine *engine) { engine_ = engine; }
+  void set_engine(CommandBufferUpcallInterface *engine) { engine_ = engine; }
  private:
   // Decodes the SET_VERTEX_INPUT command.
   ParseError DecodeSetVertexInput(unsigned int arg_count,
@@ -134,7 +134,7 @@
   #undef O3D_COMMAND_BUFFER_CMD_OP
 
   GAPIInterface *gapi_;
-  CommandBufferEngine *engine_;
+  CommandBufferUpcallInterface *engine_;
 };
 
 }  // namespace command_buffer