cc: Throttle swaps in Scheduler instead of OutputSurface

cc/scheduler/scheduler_unittest.cc

Index: cc/scheduler/scheduler_unittest.cc
diff --git a/cc/scheduler/scheduler_unittest.cc b/cc/scheduler/scheduler_unittest.cc
index fcd73a86d295b71012d34263b54bd03624e16c4e..c2b8ef9a067371b774e704b47a38ec36e0ac1218 100644
--- a/cc/scheduler/scheduler_unittest.cc
+++ b/cc/scheduler/scheduler_unittest.cc
@@ -1256,13 +1256,21 @@ TEST(SchedulerTest, PollForCommitCompletion) {
   impl_frame_args.interval = base::TimeDelta::FromMilliseconds(interval);
   scheduler->BeginImplFrame(impl_frame_args);
   scheduler->OnBeginImplFrameDeadline();
+  scheduler->DidSwapBuffers();
+  scheduler->OnSwapBuffersComplete();
 
   // At this point, we've drawn a frame.  Start another commit, but hold off on
   // the NotifyReadyToCommit for now.
   EXPECT_FALSE(scheduler->CommitPending());
+  scheduler->BeginImplFrame(impl_frame_args);
   scheduler->SetNeedsCommit();
   EXPECT_TRUE(scheduler->CommitPending());
 
+  // Draw and swap the frame, but don't ack the swap to simulate the Browser
+  // blocking on the renderer.
+  scheduler->OnBeginImplFrameDeadline();
+  scheduler->DidSwapBuffers();
+
   // Spin the event loop a few times and make sure we get more
   // DidAnticipateDrawTimeChange calls every time.
   int actions_so_far = client.num_actions_();