cc: Introduce BeginFrame sequence numbers and acknowledgements.

services/ui/surfaces/display_compositor.cc

Index: services/ui/surfaces/display_compositor.cc
diff --git a/services/ui/surfaces/display_compositor.cc b/services/ui/surfaces/display_compositor.cc
index 4c4f85a980d373f0d53dd06030df0b047b8abbc5..5f503c8ed61d92f614c74af1590594097a50b31d 100644
--- a/services/ui/surfaces/display_compositor.cc
+++ b/services/ui/surfaces/display_compositor.cc
@@ -206,8 +206,7 @@ std::unique_ptr<cc::Display> DisplayCompositor::CreateDisplay(
   DCHECK_GT(max_frames_pending, 0);
 
   std::unique_ptr<cc::DisplayScheduler> scheduler(
-      new cc::DisplayScheduler(synthetic_begin_frame_source.get(),
-                               task_runner_.get(), max_frames_pending));
+      new cc::DisplayScheduler(task_runner_.get(), max_frames_pending));
 
   return base::MakeUnique<cc::Display>(
       nullptr /* bitmap_manager */, gpu_memory_buffer_manager_.get(),