cc: Introduce BeginFrame sequence numbers and acknowledgements.

cc/surfaces/direct_compositor_frame_sink_unittest.cc

Index: cc/surfaces/direct_compositor_frame_sink_unittest.cc
diff --git a/cc/surfaces/direct_compositor_frame_sink_unittest.cc b/cc/surfaces/direct_compositor_frame_sink_unittest.cc
index 8b39040256dc9c4bb0416ab70112bf7a28f231d8..a4efb59d70aea7c10a17b06b3dff611f267f032b 100644
--- a/cc/surfaces/direct_compositor_frame_sink_unittest.cc
+++ b/cc/surfaces/direct_compositor_frame_sink_unittest.cc
@@ -47,8 +47,8 @@ class DirectCompositorFrameSinkTest : public testing::Test {
             base::MakeUnique<DelayBasedTimeSource>(task_runner_.get())));
 
     int max_frames_pending = 2;
-    std::unique_ptr<DisplayScheduler> scheduler(new DisplayScheduler(
-        begin_frame_source.get(), task_runner_.get(), max_frames_pending));
+    std::unique_ptr<DisplayScheduler> scheduler(
+        new DisplayScheduler(task_runner_.get(), max_frames_pending));
 
     display_.reset(new Display(
         &bitmap_manager_, &gpu_memory_buffer_manager_, RendererSettings(),