Revert of cc: Remove frame queuing from the scheduler.

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 164 matching lines @@
     PushAction("SendBeginMainFrameNotExpectedSoon");
   }
 
   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;
-  }
-
-  base::Callback<bool(void)> FrameHasNotAdvancedCallback() {
-    return base::Bind(&FakeSchedulerClient::IsCurrentFrame,
-                      base::Unretained(this),
-                      scheduler_->current_frame_number());
-  }
-
   void PushAction(const char* description) {
     actions_.push_back(description);
     states_.push_back(scheduler_->AsValue());
   }
 
   // FakeExternalBeginFrameSource::Client implementation.
   void OnAddObserver(BeginFrameObserver* obs) override {
     PushAction("AddObserver(this)");
   }
   void OnRemoveObserver(BeginFrameObserver* obs) override {
@@ skipping 176 matching lines @@
     EXPECT_FALSE(scheduler_->begin_frames_expected());
     client_->Reset();
   }
 
   // As this function contains EXPECT macros, to allow debugging it should be
   // called inside EXPECT_SCOPED like so;
   //   EXPECT_SCOPED(client.AdvanceFrame());
   void AdvanceFrame() {
     TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler.frames"),
                  "FakeSchedulerClient::AdvanceFrame");
+    // Consume any previous deadline first, if no deadline is currently
+    // pending, InsideBeginImplFrame will return false straight away and we
+    // will run no tasks.
+    task_runner_->RunTasksWhile(client_->InsideBeginImplFrame(true));
+    EXPECT_FALSE(client_->IsInsideBeginImplFrame());
 
     // Send the next BeginFrame message if using an external source, otherwise
     // it will be already in the task queue.
     if (scheduler_->begin_frame_source() ==
         fake_external_begin_frame_source_.get()) {
       EXPECT_TRUE(scheduler_->begin_frames_expected());
       SendNextBeginFrame();
-    } else {
-      task_runner_->RunTasksWhile(client_->FrameHasNotAdvancedCallback());
+    }
+
+    if (!scheduler_->settings().using_synchronous_renderer_compositor) {
+      // Then run tasks until new deadline is scheduled.
+      EXPECT_TRUE(
+          task_runner_->RunTasksWhile(client_->InsideBeginImplFrame(false)));
+      EXPECT_TRUE(client_->IsInsideBeginImplFrame());
     }
   }
 
   BeginFrameArgs SendNextBeginFrame() {
     DCHECK_EQ(scheduler_->begin_frame_source(),
               fake_external_begin_frame_source_.get());
     // Creep the time forward so that any BeginFrameArgs is not equal to the
     // last one otherwise we violate the BeginFrameSource contract.
     now_src_->Advance(BeginFrameArgs::DefaultInterval());
     BeginFrameArgs args =
@@ skipping 1591 matching lines @@
   EXPECT_NO_ACTION(client_);
 
   // Activate the pending tree, which also unblocks the commit immediately
   // while we are in an idle state.
   client_->Reset();
   scheduler_->NotifyReadyToActivate();
   EXPECT_ACTION("ScheduledActionActivateSyncTree", client_, 0, 2);
   EXPECT_ACTION("ScheduledActionCommit", client_, 1, 2);
 }
 
+TEST_F(SchedulerTest, BeginRetroFrame) {
+  SetUpScheduler(EXTERNAL_BFS);
+
+  // SetNeedsBeginMainFrame should begin the frame on the next BeginImplFrame.
+  scheduler_->SetNeedsBeginMainFrame();
+  EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
+  client_->Reset();
+
+  // Create a BeginFrame with a long deadline to avoid race conditions.
+  // This is the first BeginFrame, which will be handled immediately.
+  BeginFrameArgs args =
+      CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, now_src());
+  args.deadline += base::TimeDelta::FromHours(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  client_->Reset();
+
+  // Queue BeginFrames while we are still handling the previous BeginFrame.
+  args.frame_time += base::TimeDelta::FromSeconds(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+  args.frame_time += base::TimeDelta::FromSeconds(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+
+  // If we don't swap on the deadline, we wait for the next BeginImplFrame.
+  task_runner().RunPendingTasks();  // Run posted deadline.
+  EXPECT_NO_ACTION(client_);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  client_->Reset();
+
+  // NotifyReadyToCommit should trigger the commit.
+  scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
+  scheduler_->NotifyReadyToCommit();
+  EXPECT_SINGLE_ACTION("ScheduledActionCommit", client_);
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  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.
+  task_runner().RunPendingTasks();  // Run posted BeginRetroFrame.
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  client_->Reset();
+
+  // BeginImplFrame deadline should draw.
+  task_runner().RunPendingTasks();  // Run posted deadline.
+  EXPECT_ACTION("ScheduledActionDrawAndSwapIfPossible", client_, 0, 1);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  client_->Reset();
+
+  // The following BeginImplFrame deadline should SetNeedsBeginFrame(false)
+  // to avoid excessive toggles.
+  task_runner().RunPendingTasks();  // Run posted BeginRetroFrame.
+  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  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, RetroFrameDoesNotExpireTooEarly) {
+  SetUpScheduler(EXTERNAL_BFS);
+
+  scheduler_->SetNeedsBeginMainFrame();
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
+
+  client_->Reset();
+  EXPECT_SCOPED(AdvanceFrame());
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+
+  client_->Reset();
+  scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
+
+  client_->Reset();
+  BeginFrameArgs retro_frame_args = SendNextBeginFrame();
+  // This BeginFrame is queued up as a retro frame.
+  EXPECT_NO_ACTION(client_);
+  // The previous deadline is still pending.
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+
+  client_->Reset();
+  // This main frame activating should schedule the (previous) deadline to
+  // trigger immediately.
+  scheduler_->NotifyReadyToCommit();
+  scheduler_->NotifyReadyToActivate();
+  EXPECT_ACTION("ScheduledActionCommit", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionActivateSyncTree", client_, 1, 2);
+
+  client_->Reset();
+  // The deadline task should trigger causing a draw.
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+  task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
+  EXPECT_ACTION("ScheduledActionDrawAndSwapIfPossible", client_, 0, 1);
+
+  // Keep animating.
+  client_->Reset();
+  scheduler_->SetNeedsOneBeginImplFrame();
+  scheduler_->SetNeedsRedraw();
+  EXPECT_NO_ACTION(client_);
+
+  // Let's advance to the retro frame's deadline.
+  now_src()->Advance(retro_frame_args.deadline - now_src()->NowTicks());
+
+  // The retro frame hasn't expired yet.
+  task_runner().RunTasksWhile(client_->InsideBeginImplFrame(false));
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+
+  // This is an immediate deadline case.
+  client_->Reset();
+  task_runner().RunPendingTasks();
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  EXPECT_SINGLE_ACTION("ScheduledActionDrawAndSwapIfPossible", client_);
+}
+
+TEST_F(SchedulerTest, RetroFrameExpiresOnTime) {
+  SetUpScheduler(EXTERNAL_BFS);
+
+  scheduler_->SetNeedsBeginMainFrame();
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
+
+  client_->Reset();
+  EXPECT_SCOPED(AdvanceFrame());
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+
+  client_->Reset();
+  scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
+
+  client_->Reset();
+  BeginFrameArgs retro_frame_args = SendNextBeginFrame();
+  // This BeginFrame is queued up as a retro frame.
+  EXPECT_NO_ACTION(client_);
+  // The previous deadline is still pending.
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+
+  client_->Reset();
+  // This main frame activating should schedule the (previous) deadline to
+  // trigger immediately.
+  scheduler_->NotifyReadyToCommit();
+  scheduler_->NotifyReadyToActivate();
+  EXPECT_ACTION("ScheduledActionCommit", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionActivateSyncTree", client_, 1, 2);
+
+  client_->Reset();
+  // The deadline task should trigger causing a draw.
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+  task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
+  EXPECT_ACTION("ScheduledActionDrawAndSwapIfPossible", client_, 0, 1);
+
+  // Keep animating.
+  client_->Reset();
+  scheduler_->SetNeedsOneBeginImplFrame();
+  scheduler_->SetNeedsRedraw();
+  EXPECT_NO_ACTION(client_);
+
+  // Let's advance sufficiently past the retro frame's deadline.
+  now_src()->Advance(retro_frame_args.deadline - now_src()->NowTicks() +
+                     base::TimeDelta::FromMicroseconds(1));
+
+  // The retro frame should've expired.
+  EXPECT_NO_ACTION(client_);
+}
+
+TEST_F(SchedulerTest, MissedFrameDoesNotExpireTooEarly) {
+  SetUpScheduler(EXTERNAL_BFS);
+
+  scheduler_->SetNeedsBeginMainFrame();
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
+
+  BeginFrameArgs missed_frame_args =
+      CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, now_src());
+  missed_frame_args.type = BeginFrameArgs::MISSED;
+
+  // Advance to the deadline.
+  now_src()->Advance(missed_frame_args.deadline - now_src()->NowTicks());
+
+  // Missed frame is handled because it's on time.
+  client_->Reset();
+  fake_external_begin_frame_source_->TestOnBeginFrame(missed_frame_args);
+  EXPECT_TRUE(
+      task_runner().RunTasksWhile(client_->InsideBeginImplFrame(false)));
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+}
+
+TEST_F(SchedulerTest, MissedFrameExpiresOnTime) {
+  SetUpScheduler(EXTERNAL_BFS);
+
+  scheduler_->SetNeedsBeginMainFrame();
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+  EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
+
+  BeginFrameArgs missed_frame_args =
+      CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, now_src());
+  missed_frame_args.type = BeginFrameArgs::MISSED;
+
+  // Advance sufficiently past the deadline.
+  now_src()->Advance(missed_frame_args.deadline - now_src()->NowTicks() +
+                     base::TimeDelta::FromMicroseconds(1));
+
+  // Missed frame is dropped because it's too late.
+  client_->Reset();
+  fake_external_begin_frame_source_->TestOnBeginFrame(missed_frame_args);
+  EXPECT_FALSE(
+      task_runner().RunTasksWhile(client_->InsideBeginImplFrame(false)));
+  EXPECT_NO_ACTION(client_);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+}
+
 void SchedulerTest::BeginFramesNotFromClient(BeginFrameSourceType bfs_type) {
   SetUpScheduler(bfs_type);
 
   // SetNeedsBeginMainFrame should begin the frame on the next BeginImplFrame
   // without calling SetNeedsBeginFrame.
   scheduler_->SetNeedsBeginMainFrame();
   EXPECT_NO_ACTION(client_);
   client_->Reset();
 
-  EXPECT_SCOPED(AdvanceFrame());
-  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
-  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
-  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
-  client_->Reset();
-
-  // Can't run the deadline task because it can race with begin frame for the
-  // SyntheticBFS case.
-  EXPECT_SCOPED(AdvanceFrame());
+  // When the client-driven BeginFrame are disabled, the scheduler posts it's
+  // own BeginFrame tasks.
+  task_runner().RunPendingTasks();  // Run posted BeginFrame.
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", 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_NO_ACTION(client_);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  client_->Reset();
+
+  // NotifyReadyToCommit should trigger the commit.
+  scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
+  scheduler_->NotifyReadyToCommit();
+  EXPECT_SINGLE_ACTION("ScheduledActionCommit", client_);
+  client_->Reset();
+
+  // NotifyReadyToActivate should trigger the activation.
+  scheduler_->NotifyReadyToActivate();
+  EXPECT_SINGLE_ACTION("ScheduledActionActivateSyncTree", client_);
+  client_->Reset();
+
+  // BeginImplFrame should prepare the draw.
+  task_runner().RunPendingTasks();  // Run posted BeginFrame.
   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_);
-  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("ScheduledActionDrawAndSwapIfPossible", client_, 0, 2);
-  EXPECT_ACTION("WillBeginImplFrame", client_, 1, 2);
+  // BeginImplFrame deadline should draw.
+  task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
+  EXPECT_ACTION("ScheduledActionDrawAndSwapIfPossible", client_, 0, 1);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  client_->Reset();
+
+  // The following BeginImplFrame deadline should SetNeedsBeginFrame(false)
+  // to avoid excessive toggles.
+  task_runner().RunPendingTasks();  // Run posted BeginFrame.
+  EXPECT_SINGLE_ACTION("WillBeginImplFrame", client_);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
   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 247 matching lines @@
 
   client_->Reset();
   task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
   EXPECT_ACTION("ScheduledActionPrepareTiles", client_, 0, 4);
   EXPECT_ACTION("ScheduledActionBeginCompositorFrameSinkCreation", client_, 1,
                 4);
   EXPECT_ACTION("RemoveObserver(this)", client_, 2, 4);
   EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 3, 4);
 }
 
+TEST_F(SchedulerTest, DidLoseCompositorFrameSinkAfterBeginRetroFramePosted) {
+  SetUpScheduler(EXTERNAL_BFS);
+
+  // SetNeedsBeginMainFrame should begin the frame on the next BeginImplFrame.
+  scheduler_->SetNeedsBeginMainFrame();
+  EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
+
+  // Create a BeginFrame with a long deadline to avoid race conditions.
+  // This is the first BeginFrame, which will be handled immediately.
+  client_->Reset();
+  BeginFrameArgs args =
+      CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, now_src());
+  args.deadline += base::TimeDelta::FromHours(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  // Queue BeginFrames while we are still handling the previous BeginFrame.
+  args.frame_time += base::TimeDelta::FromSeconds(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+  args.frame_time += base::TimeDelta::FromSeconds(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+
+  // If we don't swap on the deadline, we wait for the next BeginImplFrame.
+  client_->Reset();
+  task_runner().RunPendingTasks();  // Run posted deadline.
+  EXPECT_NO_ACTION(client_);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  // NotifyReadyToCommit should trigger the commit.
+  client_->Reset();
+  scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
+  scheduler_->NotifyReadyToCommit();
+  EXPECT_SINGLE_ACTION("ScheduledActionCommit", client_);
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  // NotifyReadyToActivate should trigger the activation.
+  client_->Reset();
+  scheduler_->NotifyReadyToActivate();
+  EXPECT_SINGLE_ACTION("ScheduledActionActivateSyncTree", client_);
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  client_->Reset();
+  EXPECT_FALSE(scheduler_->IsBeginRetroFrameArgsEmpty());
+  scheduler_->DidLoseCompositorFrameSink();
+  EXPECT_ACTION("ScheduledActionBeginCompositorFrameSinkCreation", client_, 0,
+                3);
+  EXPECT_ACTION("RemoveObserver(this)", client_, 1, 3);
+  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 2, 3);
+  EXPECT_TRUE(scheduler_->IsBeginRetroFrameArgsEmpty());
+
+  // Posted BeginRetroFrame is aborted.
+  client_->Reset();
+  task_runner().RunPendingTasks();
+  EXPECT_NO_ACTION(client_);
+}
+
+TEST_F(SchedulerTest, DidLoseCompositorFrameSinkDuringBeginRetroFrameRunning) {
+  SetUpScheduler(EXTERNAL_BFS);
+
+  // SetNeedsBeginMainFrame should begin the frame on the next BeginImplFrame.
+  scheduler_->SetNeedsBeginMainFrame();
+  EXPECT_SINGLE_ACTION("AddObserver(this)", client_);
+
+  // Create a BeginFrame with a long deadline to avoid race conditions.
+  // This is the first BeginFrame, which will be handled immediately.
+  client_->Reset();
+  BeginFrameArgs args =
+      CreateBeginFrameArgsForTesting(BEGINFRAME_FROM_HERE, now_src());
+  args.deadline += base::TimeDelta::FromHours(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 2);
+  EXPECT_ACTION("ScheduledActionSendBeginMainFrame", client_, 1, 2);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  // Queue BeginFrames while we are still handling the previous BeginFrame.
+  args.frame_time += base::TimeDelta::FromSeconds(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+  args.frame_time += base::TimeDelta::FromSeconds(1);
+  fake_external_begin_frame_source()->TestOnBeginFrame(args);
+
+  // If we don't swap on the deadline, we wait for the next BeginImplFrame.
+  client_->Reset();
+  task_runner().RunPendingTasks();  // Run posted deadline.
+  EXPECT_NO_ACTION(client_);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  // NotifyReadyToCommit should trigger the commit.
+  client_->Reset();
+  scheduler_->NotifyBeginMainFrameStarted(base::TimeTicks());
+  scheduler_->NotifyReadyToCommit();
+  EXPECT_SINGLE_ACTION("ScheduledActionCommit", client_);
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  // NotifyReadyToActivate should trigger the activation.
+  client_->Reset();
+  scheduler_->NotifyReadyToActivate();
+  EXPECT_SINGLE_ACTION("ScheduledActionActivateSyncTree", client_);
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  // BeginImplFrame should prepare the draw.
+  client_->Reset();
+  task_runner().RunPendingTasks();  // Run posted BeginRetroFrame.
+  EXPECT_ACTION("WillBeginImplFrame", client_, 0, 1);
+  EXPECT_TRUE(client_->IsInsideBeginImplFrame());
+  EXPECT_TRUE(scheduler_->begin_frames_expected());
+
+  client_->Reset();
+  EXPECT_FALSE(scheduler_->IsBeginRetroFrameArgsEmpty());
+  scheduler_->DidLoseCompositorFrameSink();
+  EXPECT_NO_ACTION(client_);
+  EXPECT_TRUE(scheduler_->IsBeginRetroFrameArgsEmpty());
+
+  // BeginImplFrame deadline should abort drawing.
+  client_->Reset();
+  task_runner().RunTasksWhile(client_->InsideBeginImplFrame(true));
+  EXPECT_ACTION("ScheduledActionBeginCompositorFrameSinkCreation", client_, 0,
+                3);
+  EXPECT_ACTION("RemoveObserver(this)", client_, 1, 3);
+  EXPECT_ACTION("SendBeginMainFrameNotExpectedSoon", client_, 2, 3);
+  EXPECT_FALSE(client_->IsInsideBeginImplFrame());
+  EXPECT_FALSE(scheduler_->begin_frames_expected());
+
+  // No more BeginRetroFrame because BeginRetroFrame queue is cleared.
+  client_->Reset();
+  task_runner().RunPendingTasks();
+  EXPECT_NO_ACTION(client_);
+}
+
 TEST_F(SchedulerTest,
        DidLoseCompositorFrameSinkWithDelayBasedBeginFrameSource) {
   SetUpScheduler(THROTTLED_BFS);
 
   // SetNeedsBeginMainFrame should begin the frame on the next BeginImplFrame.
   EXPECT_FALSE(scheduler_->begin_frames_expected());
   scheduler_->SetNeedsBeginMainFrame();
   EXPECT_TRUE(scheduler_->begin_frames_expected());
 
   client_->Reset();
@@ skipping 902 matching lines @@
 }
 
 TEST_F(SchedulerTest, BeginMainFrameOnCriticalPath_AHS) {
   EXPECT_FALSE(BeginMainFrameOnCriticalPath(
       SMOOTHNESS_TAKES_PRIORITY,
       ScrollHandlerState::SCROLL_AFFECTS_SCROLL_HANDLER, kSlowDuration));
 }
 
 }  // namespace
 }  // namespace cc