cc: Introduce BeginFrame sequence numbers and acknowledgements.

cc/surfaces/display_unittest.cc

Index: cc/surfaces/display_unittest.cc
diff --git a/cc/surfaces/display_unittest.cc b/cc/surfaces/display_unittest.cc
index 4534edb9796002a3ec1b0f28b427f3504453ddad..06d32380fc17a6df201c4ede1f90084f0a2de7a7 100644
--- a/cc/surfaces/display_unittest.cc
+++ b/cc/surfaces/display_unittest.cc
@@ -61,9 +61,8 @@ class TestSoftwareOutputDevice : public SoftwareOutputDevice {
 
 class TestDisplayScheduler : public DisplayScheduler {
  public:
-  TestDisplayScheduler(BeginFrameSource* begin_frame_source,
-                       base::SingleThreadTaskRunner* task_runner)
-      : DisplayScheduler(begin_frame_source, task_runner, 1),
+  explicit TestDisplayScheduler(base::SingleThreadTaskRunner* task_runner)
+      : DisplayScheduler(task_runner, 1),
         damaged(false),
         display_resized_(false),
         has_new_root_surface(false),
@@ -128,7 +127,7 @@ class DisplayTest : public testing::Test {
     output_surface_ = output_surface.get();
 
     std::unique_ptr<TestDisplayScheduler> scheduler(
-        new TestDisplayScheduler(begin_frame_source.get(), task_runner_.get()));
+        new TestDisplayScheduler(task_runner_.get()));
     scheduler_ = scheduler.get();
 
     display_ = base::MakeUnique<Display>(