gpu: Implement idle async pixel transfers.

gpu/command_buffer/service/gles2_cmd_decoder.h

Index: gpu/command_buffer/service/gles2_cmd_decoder.h
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.h b/gpu/command_buffer/service/gles2_cmd_decoder.h
index cce89a47364bd20098732cf1d643f60c218c4611..ad09a8d1bbf608133328100e65163f3d2fbace30 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.h
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.h
@@ -163,6 +163,12 @@ class GPU_EXPORT GLES2Decoder : public base::SupportsWeakPtr<GLES2Decoder>,
   // Process any pending queries. Returns false if there are no pending queries.
   virtual bool ProcessPendingQueries() = 0;
 
+  // Returns false if there are no pending queries or idle tasks to be made.
+  virtual bool HasMoreWork() = 0;
+
+  // Idle work handler. Returns false if there is no pending idle work.
+  virtual bool PerformIdleWork() = 0;
+
   // Sets a callback which is called when a glResizeCHROMIUM command
   // is processed.
   virtual void SetResizeCallback(