Add OrderingBarrierCHROMIUM API.

gpu/command_buffer/service/command_buffer_service.cc

Index: gpu/command_buffer/service/command_buffer_service.cc
diff --git a/gpu/command_buffer/service/command_buffer_service.cc b/gpu/command_buffer/service/command_buffer_service.cc
index 21e2ae497ec65cfa6901f67d81111e4e9725a07f..f2444b31e9f091fd7f67c9bd41f5bcd583b385ed 100644
--- a/gpu/command_buffer/service/command_buffer_service.cc
+++ b/gpu/command_buffer/service/command_buffer_service.cc
@@ -79,6 +79,10 @@ void CommandBufferService::Flush(int32 put_offset) {
     put_offset_change_callback_.Run();
 }
 
+void CommandBufferService::OrderingBarrier(int32 put_offset) {
+  Flush(put_offset);
+}
+
 void CommandBufferService::SetGetBuffer(int32 transfer_buffer_id) {
   DCHECK_EQ(-1, ring_buffer_id_);
   DCHECK_EQ(put_offset_, get_offset_);  // Only if it's empty.