gpu: Implement idle async pixel transfers.

content/common/gpu/gpu_command_buffer_stub.h

Index: content/common/gpu/gpu_command_buffer_stub.h
diff --git a/content/common/gpu/gpu_command_buffer_stub.h b/content/common/gpu/gpu_command_buffer_stub.h
index 03de927b15f894e53a29fdb59b8ace10a1df5f71..daca081d94a1d43299b1586170f386d814bae9c6 100644
--- a/content/common/gpu/gpu_command_buffer_stub.h
+++ b/content/common/gpu/gpu_command_buffer_stub.h
@@ -191,7 +191,7 @@ class GpuCommandBufferStub
   // Whether this command buffer needs to be polled again in the future.
   bool HasMoreWork();
 
-  void ScheduleDelayedWork(int64 delay);
+  void ScheduleDelayedWork();
 
   // The lifetime of objects of this class is managed by a GpuChannel. The
   // GpuChannels destroy all the GpuCommandBufferStubs that they own when they
@@ -241,6 +241,8 @@ class GpuCommandBufferStub
   int sync_point_wait_count_;
 
   bool delayed_work_scheduled_;
+  uint64 previous_messages_processed_;
+  base::TimeTicks last_idle_time_;
 
   scoped_refptr<gpu::PreemptionFlag> preemption_flag_;