Create a new action triggered when a BeginMainFrame is not expected before vsync

cc/scheduler/scheduler_unittest.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/scheduler/scheduler.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <vector>
@@ skipping 161 matching lines @@
     states_.push_back(scheduler_->AsValue());
   }
   void ScheduledActionPerformImplSideInvalidation() override {
     PushAction("ScheduledActionPerformImplSideInvalidation");
   }
 
   void SendBeginMainFrameNotExpectedSoon() override {
     PushAction("SendBeginMainFrameNotExpectedSoon");
   }
 
+  void ScheduledActionDoShortIdleWork(const BeginFrameArgs& args) override {
+    PushAction("ScheduledActionDoShortIdleWork");
+  }
+
   bool IsInsideBeginImplFrame() const { return inside_begin_impl_frame_; }
 
   base::Callback<bool(void)> InsideBeginImplFrame(bool state) {
     return base::Bind(&FakeSchedulerClient::InsideBeginImplFrameCallback,
                       base::Unretained(this), state);
   }
 
   bool IsCurrentFrame(int last_frame_number) const {
     return scheduler_->current_frame_number() == last_frame_number;
   }
@@ skipping 282 matching lines @@
   SetUpScheduler(EXTERNAL_BFS);
 
   scheduler_->SetVideoNeedsBeginFrames(true);
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   EXPECT_TRUE(scheduler_->begin_frames_expected());
 
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   // WillBeginImplFrame is responsible for sending BeginFrames to video.
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
 
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
 
   client_->Reset();
   scheduler_->SetVideoNeedsBeginFrames(false);
   EXPECT_NO_ACTION(client_);
 
   client_->Reset();
   task_runner_->RunTasksWhile(client_->InsideBeginImplFrame(true));
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_ACTION("RemoveObserver(this)", client_, 0, 2);
   EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 1, 2);
@@ skipping 30 matching lines @@
   client_->Reset();
 
   // NotifyReadyToActivate should trigger the activation.
   scheduler_->NotifyReadyToActivate();
   EXPECT_SINGLE_ACTION("ScheduledActionActivateSyncTree", client_);
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   // BeginImplFrame should prepare the draw.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   // BeginImplFrame deadline should draw.
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   // The following BeginImplFrame deadline should SetNeedsBeginFrame(false)
   // to avoid excessive toggles.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("RemoveObserver(this)", client_, 0, 2);
   EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 1, 2);
   client_->Reset();
 }
 
 TEST_F(SchedulerTest, RequestCommitAfterSetDeferCommit) {
@@ skipping 399 matching lines @@
   EXPECT_TRUE(scheduler_->PrepareTilesPending());
   EXPECT_TRUE(client->needs_begin_frames());
   EXPECT_EQ(0, client->num_draws());
   EXPECT_FALSE(client->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(client->HasAction("ScheduledActionDrawIfPossible"));
 
   // We have no immediate actions to perform, so the BeginImplFrame should post
   // the deadline task.
   client->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   // On the deadline, the actions should have occured in the right order.
   client->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(1, client->num_draws());
   EXPECT_TRUE(client->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_TRUE(client->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_LT(client->ActionIndex("ScheduledActionDrawIfPossible"),
             client->ActionIndex("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(scheduler_->RedrawPending());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
   // Request a draw. We don't need a PrepareTiles yet.
   client->Reset();
   scheduler_->SetNeedsRedraw();
   EXPECT_TRUE(scheduler_->RedrawPending());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   EXPECT_TRUE(client->needs_begin_frames());
   EXPECT_EQ(0, client->num_draws());
 
   // We have no immediate actions to perform, so the BeginImplFrame should post
   // the deadline task.
   client->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   // Draw. The draw will trigger SetNeedsPrepareTiles, and
   // then the PrepareTiles action will be triggered after the Draw.
   // Afterwards, neither a draw nor PrepareTiles are pending.
   client->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(1, client->num_draws());
   EXPECT_TRUE(client->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_TRUE(client->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_LT(client->ActionIndex("ScheduledActionDrawIfPossible"),
             client->ActionIndex("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(scheduler_->RedrawPending());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
   // We need a BeginImplFrame where we don't swap to go idle.
   client->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client);
+  EXPECT_ACTION("WillBeginImplFrame", client, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("RemoveObserver(this)", client_, 0, 2);
   EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 1, 2);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_EQ(0, client->num_draws());
 
   // Now trigger a PrepareTiles outside of a draw. We will then need
   // a begin-frame for the PrepareTiles, but we don't need a draw.
   client->Reset();
   EXPECT_FALSE(client->needs_begin_frames());
   scheduler_->SetNeedsPrepareTiles();
   EXPECT_TRUE(client->needs_begin_frames());
   EXPECT_TRUE(scheduler_->PrepareTilesPending());
   EXPECT_FALSE(scheduler_->RedrawPending());
 
   // BeginImplFrame. There will be no draw, only PrepareTiles.
   client->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client);
+  EXPECT_ACTION("WillBeginImplFrame", client, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(0, client->num_draws());
   EXPECT_FALSE(client->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_TRUE(client->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 }
 
 // Test that PrepareTiles only happens once per frame.  If an external caller
 // initiates it, then the state machine should not PrepareTiles on that frame.
 TEST_F(SchedulerTest, PrepareTilesOncePerFrame) {
   SetUpScheduler(EXTERNAL_BFS);
 
   // If DidPrepareTiles during a frame, then PrepareTiles should not occur
   // again.
   scheduler_->SetNeedsPrepareTiles();
   scheduler_->SetNeedsRedraw();
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   EXPECT_TRUE(scheduler_->PrepareTilesPending());
   scheduler_->WillPrepareTiles();
   scheduler_->DidPrepareTiles();  // An explicit PrepareTiles.
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
 
   client_->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(1, client_->num_draws());
   EXPECT_TRUE(client_->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_FALSE(client_->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(scheduler_->RedrawPending());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
   // Next frame without DidPrepareTiles should PrepareTiles with draw.
   scheduler_->SetNeedsPrepareTiles();
   scheduler_->SetNeedsRedraw();
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   client_->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(1, client_->num_draws());
   EXPECT_TRUE(client_->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_TRUE(client_->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_LT(client_->ActionIndex("ScheduledActionDrawIfPossible"),
             client_->ActionIndex("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(scheduler_->RedrawPending());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
   // If we get another DidPrepareTiles within the same frame, we should
   // not PrepareTiles on the next frame.
   scheduler_->WillPrepareTiles();
   scheduler_->DidPrepareTiles();  // An explicit PrepareTiles.
   scheduler_->SetNeedsPrepareTiles();
   scheduler_->SetNeedsRedraw();
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   EXPECT_TRUE(scheduler_->PrepareTilesPending());
 
   client_->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(1, client_->num_draws());
   EXPECT_TRUE(client_->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_FALSE(client_->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(scheduler_->RedrawPending());
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
   // If we get another DidPrepareTiles, we should not PrepareTiles on the next
   // frame. This verifies we don't alternate calling PrepareTiles once and
   // twice.
   EXPECT_TRUE(scheduler_->PrepareTilesPending());
   scheduler_->WillPrepareTiles();
   scheduler_->DidPrepareTiles();  // An explicit PrepareTiles.
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   scheduler_->SetNeedsPrepareTiles();
   scheduler_->SetNeedsRedraw();
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   EXPECT_TRUE(scheduler_->PrepareTilesPending());
 
   client_->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(1, client_->num_draws());
   EXPECT_TRUE(client_->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_FALSE(client_->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(scheduler_->RedrawPending());
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
   // Next frame without DidPrepareTiles should PrepareTiles with draw.
   scheduler_->SetNeedsPrepareTiles();
   scheduler_->SetNeedsRedraw();
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   client_->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_EQ(1, client_->num_draws());
   EXPECT_TRUE(client_->HasAction("ScheduledActionDrawIfPossible"));
   EXPECT_TRUE(client_->HasAction("ScheduledActionPrepareTiles"));
   EXPECT_LT(client_->ActionIndex("ScheduledActionDrawIfPossible"),
             client_->ActionIndex("ScheduledActionPrepareTiles"));
   EXPECT_FALSE(scheduler_->RedrawPending());
@@ skipping 16 matching lines @@
     scheduler_->WillPrepareTiles();
     scheduler_->DidPrepareTiles();
   }
 
   client_->Reset();
   scheduler_->SetNeedsRedraw();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
 
   client_->Reset();
   AdvanceFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   client_->Reset();
   task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 2);
   EXPECT_ACTION("ScheduledActionPrepareTiles", client_, 1, 2);
 }
 
 TEST_F(SchedulerTest, TriggerBeginFrameDeadlineEarly) {
@@ skipping 466 matching lines @@
   // still expect to recover impl thread latency if there are no commits from
   // the main thread.
   fake_compositor_timing_history_->SetAllEstimatesTo(kSlowDuration);
   fake_compositor_timing_history_->SetDrawDurationEstimate(kFastDuration);
 
   // Draw and swap for first BeginFrame
   client_->Reset();
   scheduler_->SetNeedsRedraw();
   EXPECT_FALSE(scheduler_->MainThreadMissedLastDeadline());
   SendNextBeginFrame();
-  EXPECT_ACTION("AddObserver(this)", client_, 0, 2);
-  EXPECT_ACTION("WillBeginImplFrame", client_, 1, 2);
+  EXPECT_ACTION("AddObserver(this)", client_, 0, 3);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
 
   client_->Reset();
   EXPECT_FALSE(scheduler_->MainThreadMissedLastDeadline());
   task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
 
   // Verify we skip every other frame if the swap ack consistently
   // comes back late.
   for (int i = 0; i < 10; i++) {
     // Not calling scheduler_->DidReceiveCompositorFrameAck() until after next
@@ skipping 11 matching lines @@
     // swap throttled.
     client_->Reset();
     scheduler_->DidReceiveCompositorFrameAck();
     EXPECT_NO_ACTION(client_);
 
     // Verify that we start the next BeginImplFrame and continue normally
     // after having just skipped a BeginImplFrame.
     client_->Reset();
     EXPECT_FALSE(scheduler_->MainThreadMissedLastDeadline());
     SendNextBeginFrame();
-    EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+    EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+    EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
 
     client_->Reset();
     // Deadline should be immediate.
     EXPECT_TRUE(client_->IsInsideBeginImplFrame());
     task_runner().RunUntilTime(now_src_->NowTicks());
     EXPECT_FALSE(client_->IsInsideBeginImplFrame());
     EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   }
 }
 
@@ skipping 357 matching lines @@
   // Can't run the deadline task because it can race with begin frame for the
   // SyntheticBFS case.
   EXPECT_SCOPED(AdvanceFrame());
   EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // NotifyReadyToCommit should trigger the commit.
   scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
   scheduler_->NotifyReadyToCommit();
-  EXPECT_SINGLE_ACTION("ScheduledActionCommit", client_);
+  EXPECT_ACTION("ScheduledActionCommit", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   client_->Reset();
 
   // NotifyReadyToActivate should trigger the activation.
   scheduler_->NotifyReadyToActivate();
   EXPECT_SINGLE_ACTION("ScheduledActionActivateSyncTree", client_);
   client_->Reset();
 
   // BeginImplFrame deadline should draw. The following BeginImplFrame deadline
   // should SetNeedsBeginFrame(false) to avoid excessive toggles.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 2);
-  EXPECT_ACTION("WillBeginImplFrame", client_, 1, 2);
+  EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 3);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
   client_->Reset();
 
   // Make sure SetNeedsBeginFrame isn't called on the client
   // when the BeginFrame is no longer needed.
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_SINGLE_ACTION("SendBeginMainFrameNotExpectedSoon", client_);
   client_->Reset();
 }
 
 TEST_F(SchedulerTest, SyntheticBeginFrames) {
@@ skipping 230 matching lines @@
 
 TEST_F(SchedulerTest, DidLoseCompositorFrameSinkAfterSetNeedsPrepareTiles) {
   SetUpScheduler(EXTERNAL_BFS);
 
   scheduler_->SetNeedsPrepareTiles();
   scheduler_->SetNeedsRedraw();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
 
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
 
   client_->Reset();
   scheduler_->DidLoseCompositorFrameSink();
   // RemoveObserver(this) is not called until the end of the frame.
   EXPECT_NO_ACTION(client_);
 
   client_->Reset();
   task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
   EXPECT_ACTION("ScheduledActionPrepareTiles", client_, 0, 4);
@@ skipping 140 matching lines @@
 // Tests to ensure frame sources can be successfully changed while drawing.
 TEST_F(SchedulerTest, SwitchFrameSourceToUnthrottled) {
   SetUpScheduler(EXTERNAL_BFS);
 
   // SetNeedsRedraw should begin the frame on the next BeginImplFrame.
   scheduler_->SetNeedsRedraw();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   client_->Reset();
 
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
   scheduler_->SetNeedsRedraw();
 
   // Switch to an unthrottled frame source.
   scheduler_->SetBeginFrameSource(unthrottled_frame_source_.get());
   client_->Reset();
 
   // Unthrottled frame source will immediately begin a new frame.
   task_runner().RunPendingTasks();  // Run posted BeginFrame.
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // If we don't swap on the deadline, we wait for the next BeginFrame.
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 }
 
 // Tests to ensure frame sources can be successfully changed while a frame
 // deadline is pending.
 TEST_F(SchedulerTest, SwitchFrameSourceToUnthrottledBeforeDeadline) {
   SetUpScheduler(EXTERNAL_BFS);
 
   // SetNeedsRedraw should begin the frame on the next BeginImplFrame.
   scheduler_->SetNeedsRedraw();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   client_->Reset();
 
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
 
   // Switch to an unthrottled frame source before the frame deadline is hit.
   scheduler_->SetBeginFrameSource(unthrottled_frame_source_.get());
   client_->Reset();
 
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
-  EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 3);
   // Unthrottled frame source will immediately begin a new frame.
-  EXPECT_ACTION("WillBeginImplFrame", client_, 1, 2);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
   scheduler_->SetNeedsRedraw();
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 }
 
 // Tests to ensure that the active frame source can successfully be changed from
 // unthrottled to throttled.
 TEST_F(SchedulerTest, SwitchFrameSourceToThrottled) {
   SetUpScheduler(UNTHROTTLED_BFS);
 
   scheduler_->SetNeedsRedraw();
   EXPECT_NO_ACTION(client_);
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted BeginFrame.
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // Switch to a throttled frame source.
   scheduler_->SetBeginFrameSource(fake_external_begin_frame_source_.get());
   client_->Reset();
 
   // SetNeedsRedraw should begin the frame on the next BeginImplFrame.
   scheduler_->SetNeedsRedraw();
   task_runner().RunPendingTasks();
   EXPECT_NO_ACTION(client_);
   client_->Reset();
 
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
 }
 
 TEST_F(SchedulerTest, SwitchFrameSourceToNullInsideDeadline) {
   SetUpScheduler(EXTERNAL_BFS);
 
   scheduler_->SetNeedsRedraw();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   client_->Reset();
 
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   client_->Reset();
 
   // Switch to a null frame source.
   scheduler_->SetBeginFrameSource(nullptr);
   EXPECT_SINGLE_ACTION("RemoveObserver(this)", client_);
   client_->Reset();
 
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
@@ skipping 101 matching lines @@
   EXPECT_ACTION("WillBeginImplFrame", client_, 0, 5);
   EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 5);
   EXPECT_ACTION("ScheduledActionCommit", client_, 2, 5);
   EXPECT_ACTION("ScheduledActionActivateSyncTree", client_, 3, 5);
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 4, 5);
   client_->Reset();
 
   // The following BeginImplFrame deadline should SetNeedsBeginFrame(false)
   // and send a SendBeginMainFrameNotExpectedSoon.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("RemoveObserver(this)", client_, 0, 2);
   EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 1, 2);
   client_->Reset();
 }
 
 TEST_F(SchedulerTest, SynchronousCompositorAnimation) {
   scheduler_settings_.using_synchronous_renderer_compositor = true;
   SetUpScheduler(EXTERNAL_BFS);
 
   scheduler_->SetNeedsOneBeginImplFrame();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   client_->Reset();
 
   // Testing the case where animation ticks a fling scroll.
   client_->SetWillBeginImplFrameCausesRedraw(true);
   // The animation isn't done so it'll cause another tick in the future.
   client_->SetWillBeginImplFrameRequestsOneBeginImplFrame(true);
 
   // Next vsync.
   AdvanceFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
-  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 2);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
+  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 2, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 3);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // Android onDraw. This doesn't consume the single begin frame request.
   scheduler_->SetNeedsRedraw();
   bool resourceless_software_draw = false;
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // The animation inside of WillBeginImplFrame changes stuff on the screen, but
   // ends here, so does not cause another frame to happen.
   client_->SetWillBeginImplFrameCausesRedraw(true);
 
   // Next vsync.
   AdvanceFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
-  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 2);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
+  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // Android onDraw.
   scheduler_->SetNeedsRedraw();
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // Idle on next vsync, as the animation has completed.
   AdvanceFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
-  EXPECT_ACTION("RemoveObserver(this)", client_, 1, 3);
-  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 2, 3);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 4);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 4);
+  EXPECT_ACTION("RemoveObserver(this)", client_, 2, 4);
+  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 3, 4);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 }
 
 TEST_F(SchedulerTest, SynchronousCompositorOnDrawDuringIdle) {
   scheduler_settings_.using_synchronous_renderer_compositor = true;
   SetUpScheduler(EXTERNAL_BFS);
 
   scheduler_->SetNeedsRedraw();
   bool resourceless_software_draw = false;
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_ACTION("AddObserver(this)", client_, 0, 2);
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 1, 2);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // Idle on next vsync.
   AdvanceFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
-  EXPECT_ACTION("RemoveObserver(this)", client_, 1, 3);
-  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 2, 3);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 4);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 4);
+  EXPECT_ACTION("RemoveObserver(this)", client_, 2, 4);
+  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 3, 4);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 }
 
 TEST_F(SchedulerTest, SetNeedsOneBeginImplFrame) {
   SetUpScheduler(EXTERNAL_BFS);
 
   EXPECT_FALSE(scheduler_->begin_frames_expected());
 
   // Request a frame, should kick the source.
   scheduler_->SetNeedsOneBeginImplFrame();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   client_->Reset();
 
   // The incoming WillBeginImplFrame will request another one.
   client_->SetWillBeginImplFrameRequestsOneBeginImplFrame(true);
 
   // Next vsync, the first requested frame happens.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // We don't request another frame here.
 
   // Next vsync, the second requested frame happens (the one requested inside
   // the previous frame's begin impl frame step).
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // End that frame's deadline.
   task_runner_->RunTasksWhile(client_->InsideBeginImplFrame(true));
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
   // Scheduler shuts down the source now that no begin frame is requested.
   EXPECT_ACTION("RemoveObserver(this)", client_, 0, 2);
   EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 1, 2);
@@ skipping 40 matching lines @@
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   has_damage = false;
   EXPECT_EQ(
       BeginFrameAck(args.source_id, args.sequence_number,
                     latest_confirmed_sequence_number, 0, has_damage),
       fake_external_begin_frame_source_->LastAckForObserver(scheduler_.get()));
 
   scheduler_->NotifyReadyToCommit();
-  EXPECT_SINGLE_ACTION("ScheduledActionCommit", client_);
+  EXPECT_ACTION("ScheduledActionCommit", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   client_->Reset();
 
   scheduler_->NotifyReadyToActivate();
   EXPECT_SINGLE_ACTION("ScheduledActionActivateSyncTree", client_);
   client_->Reset();
 
   // Next vsync.
   args = SendNextBeginFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
-  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 2);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
+  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // Not confirmed yet and no damage, since not drawn yet.
   // TODO(eseckler): In the future, |has_damage = false| will prevent us from
   // filtering this ack (in CompositorExternalBeginFrameSource) and instead
   // forwarding the one attached to the later submitted CompositorFrame.
   has_damage = false;
   EXPECT_EQ(
       BeginFrameAck(args.source_id, args.sequence_number,
                     latest_confirmed_sequence_number, 0, has_damage),
       fake_external_begin_frame_source_->LastAckForObserver(scheduler_.get()));
 
   // Android onDraw.
   scheduler_->SetNeedsRedraw();
   bool resourceless_software_draw = false;
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   // Idle on next vsync.
   args = SendNextBeginFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
-  EXPECT_ACTION("RemoveObserver(this)", client_, 1, 3);
-  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 2, 3);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 4);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 4);
+  EXPECT_ACTION("RemoveObserver(this)", client_, 2, 4);
+  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 3, 4);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   client_->Reset();
 
   latest_confirmed_sequence_number = args.sequence_number;
   has_damage = false;
   EXPECT_EQ(
       BeginFrameAck(args.source_id, args.sequence_number,
                     latest_confirmed_sequence_number, 0, has_damage),
       fake_external_begin_frame_source_->LastAckForObserver(scheduler_.get()));
 }
@@ skipping 60 matching lines @@
   std::unique_ptr<FakeSchedulerClient> client =
       base::WrapUnique(new SchedulerClientSetNeedsPrepareTilesOnDraw);
   SetUpScheduler(EXTERNAL_BFS, std::move(client));
 
   scheduler_->SetNeedsRedraw();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   client_->Reset();
 
   // Next vsync.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
-  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 2);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
+  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
   client_->Reset();
 
   // Android onDraw.
   scheduler_->SetNeedsRedraw();
   bool resourceless_software_draw = false;
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 2);
   EXPECT_ACTION("ScheduledActionPrepareTiles", client_, 1, 2);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   client_->Reset();
 
   // Android onDraw.
   scheduler_->SetNeedsRedraw();
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 2);
   EXPECT_ACTION("ScheduledActionPrepareTiles", client_, 1, 2);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   client_->Reset();
 
   // Next vsync.
   EXPECT_SCOPED(AdvanceFrame());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
-  EXPECT_ACTION("RemoveObserver(this)", client_, 1, 3);
-  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 2, 3);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 4);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 4);
+  EXPECT_ACTION("RemoveObserver(this)", client_, 2, 4);
+  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 3, 4);
   EXPECT_FALSE(scheduler_->begin_frames_expected());
   client_->Reset();
 }
 
 TEST_F(SchedulerTest, SynchronousCompositorSendBeginMainFrameWhileIdle) {
   scheduler_settings_.using_synchronous_renderer_compositor = true;
   SetUpScheduler(EXTERNAL_BFS);
 
   scheduler_->SetNeedsRedraw();
   EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
   client_->Reset();
 
   // Next vsync.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
-  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 2);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
+  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
   client_->Reset();
 
   // Android onDraw.
   scheduler_->SetNeedsRedraw();
   bool resourceless_software_draw = false;
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   client_->Reset();
 
   // Simulate SetNeedsBeginMainFrame due to input event.
   scheduler_->SetNeedsBeginMainFrame();
   EXPECT_SINGLE_ACTION("ScheduledActionSendBeginMainFrame", client_);
   client_->Reset();
 
   scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
   scheduler_->NotifyReadyToCommit();
   EXPECT_SINGLE_ACTION("ScheduledActionCommit", client_);
   client_->Reset();
 
   scheduler_->NotifyReadyToActivate();
   EXPECT_SINGLE_ACTION("ScheduledActionActivateSyncTree", client_);
   client_->Reset();
 
   // Next vsync.
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
-  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 2);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 3);
+  EXPECT_ACTION("ScheduledActionInvalidateCompositorFrameSink", client_, 1, 3);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 2, 3);
   client_->Reset();
 
   // Android onDraw.
   scheduler_->SetNeedsRedraw();
   scheduler_->OnDrawForCompositorFrameSink(resourceless_software_draw);
   EXPECT_SINGLE_ACTION("ScheduledActionDrawIfPossible", client_);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_FALSE(scheduler_->PrepareTilesPending());
   client_->Reset();
 
@@ skipping 114 matching lines @@
 }
 
 TEST_F(SchedulerTest, ImplSideInvalidationsInDeadline) {
   SetUpScheduler(EXTERNAL_BFS);
 
   // Request an impl-side invalidation and trigger the deadline. Ensure that the
   // invalidation runs inside the deadline.
   scheduler_->SetNeedsImplSideInvalidation();
   client_->Reset();
   EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
 
   // Deadline.
   client_->Reset();
   task_runner_->RunTasksWhile(client_->InsideBeginImplFrame(true));
   EXPECT_SINGLE_ACTION("ScheduledActionPerformImplSideInvalidation", client_);
 }
 
 TEST_F(SchedulerTest, ImplSideInvalidationsMergedWithCommit) {
   SetUpScheduler(EXTERNAL_BFS);
 
@@ skipping 145 matching lines @@
                     last_begin_frame_number, latest_confirmed_sequence_number,
                     0, has_damage),
       fake_external_begin_frame_source_->LastAckForObserver(scheduler_.get()));
 
   // Run a successful redraw and verify that a new ack is sent.
   scheduler_->SetNeedsRedraw();
   client_->Reset();
 
   BeginFrameArgs args = SendNextBeginFrame();
   EXPECT_LT(latest_confirmed_sequence_number, args.sequence_number);
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   // Successful draw caused damage.
   latest_confirmed_sequence_number = args.sequence_number;
   has_damage = true;
   EXPECT_EQ(
       BeginFrameAck(args.source_id, args.sequence_number,
                     latest_confirmed_sequence_number, 0, has_damage),
       fake_external_begin_frame_source_->LastAckForObserver(scheduler_.get()));
 
   // Request another redraw, but fail it. Verify that a new ack is sent, but
   // that its |latest_confirmed_sequence_number| didn't change.
   scheduler_->SetNeedsRedraw();
   client_->Reset();
 
   args = SendNextBeginFrame();
   EXPECT_LT(latest_confirmed_sequence_number, args.sequence_number);
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   client_->SetDrawWillHappen(false);
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 2);
   // Failed draw triggers SendBeginMainFrame.
   EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
@@ skipping 14 matching lines @@
   // To get into a high latency state, this test disables automatic swap acks.
   client_->SetAutomaticSubmitCompositorFrameAck(false);
   fake_compositor_timing_history_->SetAllEstimatesTo(kFastDuration);
 
   // Run a successful redraw that submits a compositor frame but doesn't receive
   // a swap ack. Verify that a BeginFrameAck is sent for it.
   scheduler_->SetNeedsRedraw();
   client_->Reset();
 
   BeginFrameArgs args = SendNextBeginFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
@@ skipping 26 matching lines @@
 }
 
 TEST_F(SchedulerTest, BeginFrameAckForBeginFrameBeforeLastDeadline) {
   SetUpScheduler(EXTERNAL_BFS);
 
   // Request tile preparation to schedule a proactive BeginFrame.
   scheduler_->SetNeedsPrepareTiles();
   client_->Reset();
 
   SendNextBeginFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   // Until tiles were prepared, further proactive BeginFrames are expected.
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   // Send the next BeginFrame before the previous one's deadline was executed.
   // This should trigger the previous BeginFrame's deadline synchronously,
   // during which tiles will be prepared. As a result of that, no further
   // BeginFrames will be needed, and the new BeginFrame should be dropped.
   BeginFrameArgs args = SendNextBeginFrame();
@@ skipping 22 matching lines @@
   uint64_t latest_confirmed_sequence_number =
       fake_external_begin_frame_source_->next_begin_frame_number() - 1;
 
   // Request a single BeginFrame.
   scheduler_->SetNeedsOneBeginImplFrame();
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   // First BeginFrame is handled by StateMachine.
   BeginFrameArgs first_args = SendNextBeginFrame();
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   // State machine is no longer interested in BeginFrames, but scheduler is
   // still observing the source.
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   EXPECT_FALSE(scheduler_->BeginFrameNeeded());
   client_->Reset();
 
   // Send the next BeginFrame before the previous one's deadline was executed.
   // The BeginFrame should be dropped immediately, since the state machine is
   // not expecting any BeginFrames.
@@ skipping 60 matching lines @@
   scheduler_->SetNeedsRedraw();
   client_->Reset();
 
   // Send a BeginFrame with a different source_id.
   now_src_->Advance(BeginFrameArgs::DefaultInterval());
   uint32_t source_id = fake_external_begin_frame_source_->source_id() + 1;
   BeginFrameArgs args = CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE,
                                                        source_id, 1, now_src());
   fake_external_begin_frame_source_->TestOnBeginFrame(args);
 
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionDoShortIdleWork", client_, 1, 2);
   EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
   task_runner().RunPendingTasks();  // Run posted deadline.
   EXPECT_ACTION("ScheduledActionDrawIfPossible", client_, 0, 1);
   EXPECT_FALSE(client_->IsInsideBeginImplFrame());
   EXPECT_TRUE(scheduler_->begin_frames_expected());
   client_->Reset();
 
@@ skipping 34 matching lines @@
       BeginFrameArgs::kInvalidFrameNumber;
   bool has_damage = false;
   EXPECT_EQ(
       BeginFrameAck(args.source_id, args.sequence_number,
                     latest_confirmed_sequence_number, 0, has_damage),
       fake_external_begin_frame_source_->LastAckForObserver(scheduler_.get()));
 }
 
 }  // namespace
 }  // namespace cc