[cc] Add and use BeginFrameAck for DidFinishFrame.

cc/surfaces/display_scheduler_unittest.cc

Index: cc/surfaces/display_scheduler_unittest.cc
diff --git a/cc/surfaces/display_scheduler_unittest.cc b/cc/surfaces/display_scheduler_unittest.cc
index c7b5bd81802681d0c567ca61e6b31e969a7026f0..9be259982482059fd30ce815d1a57aa8aabda3ba 100644
--- a/cc/surfaces/display_scheduler_unittest.cc
+++ b/cc/surfaces/display_scheduler_unittest.cc
@@ -54,7 +54,13 @@ class TestDisplayScheduler : public DisplayScheduler {
     return DesiredBeginFrameDeadlineTime();
   }
 
-  void BeginFrameDeadlineForTest() { OnBeginFrameDeadline(); }
+  void BeginFrameDeadlineForTest() {
+    // Ensure that any missed BeginFrames were handled by the scheduler. We need
+    // to run the scheduled task ourselves since the NullTaskRunner won't.
+    if (!missed_begin_frame_task_.IsCancelled())
+      missed_begin_frame_task_.callback().Run();
+    OnBeginFrameDeadline();
+  }
 
   void ScheduleBeginFrameDeadline() override {
     scheduler_begin_frame_deadline_count_++;
@@ -65,6 +71,10 @@ class TestDisplayScheduler : public DisplayScheduler {
     return scheduler_begin_frame_deadline_count_;
   }
 
+  bool inside_begin_frame_deadline_interval() {
+    return inside_begin_frame_deadline_interval_;
+  }
+
  protected:
   int scheduler_begin_frame_deadline_count_;
 };
@@ -86,6 +96,7 @@ class DisplaySchedulerTest : public testing::Test {
   void SetUp() override { scheduler_.SetRootSurfaceResourcesLocked(false); }
 
   void BeginFrameForTest() {
+    now_src_.Advance(base::TimeDelta::FromMicroseconds(10000));

[brianderson, 2017/01/03 19:30:16]

To help test readability, can you make it explicit from the call sites that this
method will advance time? Either change the name of this method to
AdvanceTimeAndBeginFrameForTest or manually advance the time before calling
BeginFrameForTest.

[Eric Seckler, 2017/01/04 10:14:49]

Done.

     base::TimeTicks frame_time = now_src_.NowTicks();
     base::TimeDelta interval = BeginFrameArgs::DefaultInterval();
     base::TimeTicks deadline = frame_time + interval;
@@ -126,8 +137,8 @@ TEST_F(DisplaySchedulerTest, ResizeHasLateDeadlineUntilNewRootSurface) {
 
   // Resize on the next begin frame cycle should cause the deadline to wait
   // for a new root surface.
-  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   BeginFrameForTest();
+  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   scheduler_.SurfaceDamaged(sid1);
   EXPECT_GT(late_deadline, scheduler_.DesiredBeginFrameDeadlineTimeForTest());
   scheduler_.DisplayResized();
@@ -164,8 +175,8 @@ TEST_F(DisplaySchedulerTest, ResizeHasLateDeadlineUntilDamagedSurface) {
 
   // Resize on the next begin frame cycle should cause the deadline to wait
   // for a new root surface.
-  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   BeginFrameForTest();
+  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   scheduler_.SurfaceDamaged(sid1);
   EXPECT_GT(late_deadline, scheduler_.DesiredBeginFrameDeadlineTimeForTest());
   scheduler_.DisplayResized();
@@ -176,8 +187,8 @@ TEST_F(DisplaySchedulerTest, ResizeHasLateDeadlineUntilDamagedSurface) {
   scheduler_.BeginFrameDeadlineForTest();
 
   // Verify deadline goes back to normal after resize.
-  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   BeginFrameForTest();
+  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   scheduler_.SurfaceDamaged(sid1);
   EXPECT_GT(late_deadline, scheduler_.DesiredBeginFrameDeadlineTimeForTest());
   scheduler_.SurfaceDamaged(root_surface_id);
@@ -242,13 +253,12 @@ TEST_F(DisplaySchedulerTest, SurfaceDamaged) {
   BeginFrameForTest();
   scheduler_.BeginFrameDeadlineForTest();
   BeginFrameForTest();
-  scheduler_.BeginFrameDeadlineForTest();
+  EXPECT_FALSE(scheduler_.inside_begin_frame_deadline_interval());
 
   // Deadline should trigger early if child surfaces are idle and
   // we get damage on the root surface.
   BeginFrameForTest();
-  EXPECT_LT(now_src().NowTicks(),
-            scheduler_.DesiredBeginFrameDeadlineTimeForTest());
+  EXPECT_FALSE(scheduler_.inside_begin_frame_deadline_interval());
   scheduler_.SurfaceDamaged(root_surface_id);
   EXPECT_GE(now_src().NowTicks(),
             scheduler_.DesiredBeginFrameDeadlineTimeForTest());
@@ -423,8 +433,8 @@ TEST_F(DisplaySchedulerTest, RootSurfaceResourcesLocked) {
   EXPECT_EQ(1, client_.draw_and_swap_count());
 
   // Deadline triggers late while root resources are locked.
-  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   BeginFrameForTest();
+  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   scheduler_.SurfaceDamaged(sid1);
   EXPECT_GT(late_deadline, scheduler_.DesiredBeginFrameDeadlineTimeForTest());
   scheduler_.SetRootSurfaceResourcesLocked(true);
@@ -437,8 +447,8 @@ TEST_F(DisplaySchedulerTest, RootSurfaceResourcesLocked) {
   EXPECT_EQ(1, client_.draw_and_swap_count());
 
   //  Deadline triggers normally when root resources are unlocked.
-  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   BeginFrameForTest();
+  late_deadline = now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
   scheduler_.SurfaceDamaged(sid1);
   EXPECT_EQ(late_deadline, scheduler_.DesiredBeginFrameDeadlineTimeForTest());
   scheduler_.SetRootSurfaceResourcesLocked(false);
@@ -486,9 +496,9 @@ TEST_F(DisplaySchedulerTest, DidSwapBuffers) {
   scheduler_.DidSwapBuffers();
 
   // Deadline triggers late when swap throttled.
+  BeginFrameForTest();
   base::TimeTicks late_deadline =
       now_src().NowTicks() + BeginFrameArgs::DefaultInterval();
-  BeginFrameForTest();
   // Damage surface 1, but not surface 2 so we avoid triggering deadline
   // early because all surfaces are ready.
   scheduler_.SurfaceDamaged(sid1);
@@ -501,11 +511,11 @@ TEST_F(DisplaySchedulerTest, DidSwapBuffers) {
 
   // Deadline triggers normally once not swap throttled.
   // Damage from previous BeginFrame should cary over, so don't damage again.
+  scheduler_.DidReceiveSwapBuffersAck();
+  BeginFrameForTest();
   base::TimeTicks expected_deadline =
       scheduler_.LastUsedBeginFrameArgs().deadline -
       BeginFrameArgs::DefaultEstimatedParentDrawTime();
-  scheduler_.DidReceiveSwapBuffersAck();
-  BeginFrameForTest();
   EXPECT_EQ(expected_deadline,
             scheduler_.DesiredBeginFrameDeadlineTimeForTest());
   // Still waiting for surface 2. Once it updates, deadline should trigger