gpu: Implement idle async pixel transfers.

gpu/command_buffer/service/gpu_scheduler.cc

Index: gpu/command_buffer/service/gpu_scheduler.cc
diff --git a/gpu/command_buffer/service/gpu_scheduler.cc b/gpu/command_buffer/service/gpu_scheduler.cc
index 61bdcf8470e652631741885edcef724f8f94fb81..29ea7fdd507fca7c6742bb04f0afccbd04489e35 100644
--- a/gpu/command_buffer/service/gpu_scheduler.cc
+++ b/gpu/command_buffer/service/gpu_scheduler.cc
@@ -168,7 +168,8 @@ bool GpuScheduler::IsScheduled() {
 
 bool GpuScheduler::HasMoreWork() {
   return !unschedule_fences_.empty() ||
-         (decoder_ && decoder_->ProcessPendingQueries());
+         (decoder_ && decoder_->ProcessPendingQueries()) ||
+         HasMoreIdleWork();
 }
 
 void GpuScheduler::SetSchedulingChangedCallback(
@@ -269,6 +270,16 @@ bool GpuScheduler::IsPreempted() {
   return preemption_flag_->IsSet();
 }
 
+bool GpuScheduler::HasMoreIdleWork() {
+  return (decoder_ && decoder_->HasMoreIdleWork());
+}
+
+void GpuScheduler::PerformIdleWork() {
+  if (!decoder_)
+    return;
+  decoder_->PerformIdleWork();
+}
+
 void GpuScheduler::RescheduleTimeOut() {
   int new_count = unscheduled_count_ + rescheduled_count_;