Revert of Remove swap ack throttling to regain performance regression on freon

cc/scheduler/scheduler_state_machine_unittest.cc

Index: cc/scheduler/scheduler_state_machine_unittest.cc
diff --git a/cc/scheduler/scheduler_state_machine_unittest.cc b/cc/scheduler/scheduler_state_machine_unittest.cc
index 4e4a21c3fc02f7e020f9ac6ca6ccccb28da94d28..3fc4a29c8e41098982e201b8703f5cdbeac77da5 100644
--- a/cc/scheduler/scheduler_state_machine_unittest.cc
+++ b/cc/scheduler/scheduler_state_machine_unittest.cc
@@ -1759,6 +1759,16 @@
   // Finish the previous commit and draw it.
   FinishPreviousCommitAndDrawWithoutExitingDeadline(&state);
   EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  // Verify we do not send another BeginMainFrame if was are swap throttled
+  // and did not just swap.
+  state.SetNeedsCommit();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginImplFrame();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  EXPECT_FALSE(state.ShouldTriggerBeginImplFrameDeadlineImmediately());
+  state.OnBeginImplFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest,