cc: Don't swap throttle BeginMainFrame just after swapping

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 f862bafa006af32f9df9b5e6781d0ec8c30d0c62..b5834241d8cb50338b28818a221ab4568937964f 100644
--- a/cc/scheduler/scheduler_state_machine_unittest.cc
+++ b/cc/scheduler/scheduler_state_machine_unittest.cc
@@ -1723,7 +1723,32 @@ TEST(SchedulerStateMachineTest, TestTriggerDeadlineEarlyAfterAbortedCommit) {
   EXPECT_TRUE(state.ShouldTriggerBeginImplFrameDeadlineEarly());
 }
 
-TEST(SchedulerStateMachineTest, TestTriggerDeadlineEarlyForSmoothness) {
+void FinishPreviousCommitAndDrawWithoutExitingDeadline(
+    StateMachine* state_ptr) {
+  // Gross, but allows us to use macros below.
+  StateMachine& state = *state_ptr;
+
+  state.NotifyBeginMainFrameStarted();
+  state.NotifyReadyToCommit();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.NotifyReadyToActivate();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_ACTIVATE_PENDING_TREE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  state.OnBeginImplFrame(CreateBeginFrameArgsForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_ANIMATE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  EXPECT_TRUE(state.ShouldTriggerBeginImplFrameDeadlineEarly());
+  state.OnBeginImplFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  state.DidSwapBuffers();
+}
+
+TEST(SchedulerStateMachineTest, TestSmoothnessTakesPriority) {
   SchedulerSettings settings;
   settings.impl_side_painting = true;
   StateMachine state(settings);
@@ -1735,18 +1760,50 @@ TEST(SchedulerStateMachineTest, TestTriggerDeadlineEarlyForSmoothness) {
 
   // This test ensures that impl-draws are prioritized over main thread updates
   // in prefer smoothness mode.
-  state.OnBeginImplFrame(CreateBeginFrameArgsForTesting());
   state.SetNeedsRedraw(true);
   state.SetNeedsCommit();
+  state.OnBeginImplFrame(CreateBeginFrameArgsForTesting());
   EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_ANIMATE);
   EXPECT_ACTION_UPDATE_STATE(
       SchedulerStateMachine::ACTION_SEND_BEGIN_MAIN_FRAME);
   EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
-  // The deadline is not triggered early until we enter prefer smoothness mode.
+  // Verify the deadline is not triggered early until we enter
+  // prefer smoothness mode.
   EXPECT_FALSE(state.ShouldTriggerBeginImplFrameDeadlineEarly());
   state.SetSmoothnessTakesPriority(true);
   EXPECT_TRUE(state.ShouldTriggerBeginImplFrameDeadlineEarly());
+
+  // Trigger the deadline.
+  state.OnBeginImplFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  state.DidSwapBuffers();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.DidSwapBuffersComplete();
+
+  // Request a new commit and finish the previous one.
+  state.SetNeedsCommit();
+  FinishPreviousCommitAndDrawWithoutExitingDeadline(&state);
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_MAIN_FRAME);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.DidSwapBuffersComplete();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  // 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(CreateBeginFrameArgsForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  EXPECT_FALSE(state.ShouldTriggerBeginImplFrameDeadlineEarly());
+  state.OnBeginImplFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, TestTriggerDeadlineEarlyOnLostOutputSurface) {