Rework FlushSync to return early if commands have been processed since the last update

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 408d56dd0f6572f344921281dc60c1a5f12556bb..1438dc625efb6e8bb9ba8b837b0f47569d55f2cc 100644
--- a/gpu/command_buffer/service/gpu_scheduler.cc
+++ b/gpu/command_buffer/service/gpu_scheduler.cc
@@ -115,6 +115,16 @@ const unsigned int kMaxOutstandingSwapBuffersCallsPerOnscreenContext = 1;
 }
 #endif
 
+void GpuScheduler::PutChanged(bool sync) {
+  CommandBuffer::State state = command_buffer_->GetState();
+  parser_->set_put(state.put_offset);
+
+  if (sync)
+    ProcessCommands();
+  else
+    ScheduleProcessCommands();
+}
+
 void GpuScheduler::ProcessCommands() {
   GPU_TRACE_EVENT0("gpu", "GpuScheduler:ProcessCommands");
   CommandBuffer::State state = command_buffer_->GetState();
@@ -129,8 +139,6 @@ void GpuScheduler::ProcessCommands() {
     }
   }
 
-  parser_->set_put(state.put_offset);
-
 #if defined(OS_MACOSX)
   bool do_rate_limiting = surface_.get() != NULL;
   // Don't swamp the browser process with SwapBuffers calls it can't handle.