cc: Use BeginFrameArgs

cc/scheduler/scheduler_state_machine_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_state_machine.h"
 
 #include "cc/scheduler/scheduler.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#define EXPECT_ACTION_UPDATE_STATE(action) \
+  EXPECT_EQ(action, state.NextAction()) << state.ToString(); \
+  if (action == SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE || \
+      action == SchedulerStateMachine::ACTION_DRAW_AND_SWAP_FORCED) { \
+    if (SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW == \
+          state.CommitState() && \
+        SchedulerStateMachine::OUTPUT_SURFACE_ACTIVE != \
+          state.output_surface_state()) \
+      return; \
+    EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE, \
+              state.begin_frame_state()) << state.ToString(); \
+  } \
+  state.UpdateState(action); \
+  if (action == SchedulerStateMachine::ACTION_NONE) { \
+    state.AdvanceBeginFrameStateWhenNoActionsRemain(); \
+  }
+
 namespace cc {
 
 namespace {
 
+const SchedulerStateMachine::BeginFrameState all_begin_frame_states[] = {
+    SchedulerStateMachine::BEGIN_FRAME_STATE_IDLE,
+    SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_BEGIN_FRAME,
+    SchedulerStateMachine::BEGIN_FRAME_STATE_DEADLINE_PENDING,
+    SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE,
+};
+
 const SchedulerStateMachine::CommitState all_commit_states[] = {
-  SchedulerStateMachine::COMMIT_STATE_IDLE,
-  SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
-  SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
-  SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW
+    SchedulerStateMachine::COMMIT_STATE_IDLE,
+    SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
+    SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
+    SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_ACTIVATION,
+    SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
+    SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW,
 };
 
 // Exposes the protected state fields of the SchedulerStateMachine for testing
 class StateMachine : public SchedulerStateMachine {
  public:
   explicit StateMachine(const SchedulerSettings& scheduler_settings)
       : SchedulerStateMachine(scheduler_settings) {}
   void SetCommitState(CommitState cs) { commit_state_ = cs; }
   CommitState CommitState() const { return commit_state_; }
 
+  void SetBeginFrameState(BeginFrameState bfs) { begin_frame_state_ = bfs; }
+  BeginFrameState begin_frame_state() const { return begin_frame_state_; }
+
+  OutputSurfaceState output_surface_state() {
+    return output_surface_state_;
+  }
+
   bool NeedsCommit() const { return needs_commit_; }
 
   void SetNeedsRedraw(bool b) { needs_redraw_ = b; }
   bool NeedsRedraw() const { return needs_redraw_; }
 
-  void SetNeedsForcedRedraw(bool b) { needs_forced_redraw_ = b; }
-  bool NeedsForcedRedraw() const { return needs_forced_redraw_; }
+  void SetNeedsForcedRedrawForTimeout(bool b) {
+    forced_redraw_state_ = FORCED_REDRAW_STATE_WAITING_FOR_COMMIT;
+  }
+  bool NeedsForcedRedrawForTimeout() const {
+    return forced_redraw_state_ != FORCED_REDRAW_STATE_IDLE;
+  }
+
+  void SetNeedsForcedRedrawForReadback() {
+    readback_state_ = READBACK_STATE_WAITING_FOR_DRAW_AND_READBACK;
+  }
+
+  bool NeedsForcedRedrawForReadback() const {
+    return readback_state_ != READBACK_STATE_IDLE;
+  }
 
   bool CanDraw() const { return can_draw_; }
   bool Visible() const { return visible_; }
 };
 
 TEST(SchedulerStateMachineTest, TestNextActionBeginsMainFrameIfNeeded) {
   SchedulerSettings default_scheduler_settings;
 
   // If no commit needed, do nothing.
   {
     StateMachine state(default_scheduler_settings);
     state.SetCanStart();
     state.UpdateState(state.NextAction());
     state.DidCreateAndInitializeOutputSurface();
     state.SetCommitState(SchedulerStateMachine::COMMIT_STATE_IDLE);
     state.SetNeedsRedraw(false);
     state.SetVisible(true);
 
-    EXPECT_FALSE(state.BeginFrameNeededToDrawByImplThread());
+    EXPECT_FALSE(state.BeginFrameNeededByImplThread());
 
-    state.DidLeaveBeginFrame();
-    EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-    EXPECT_FALSE(state.BeginFrameNeededToDrawByImplThread());
-    state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-    EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+    EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+    EXPECT_FALSE(state.BeginFrameNeededByImplThread());
+    state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+
+    EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+    state.OnBeginFrameDeadline();
   }
 
   // If commit requested but can_start is still false, do nothing.
   {
     StateMachine state(default_scheduler_settings);
     state.SetCommitState(SchedulerStateMachine::COMMIT_STATE_IDLE);
     state.SetNeedsRedraw(false);
     state.SetVisible(true);
 
-    EXPECT_FALSE(state.BeginFrameNeededToDrawByImplThread());
+    EXPECT_FALSE(state.BeginFrameNeededByImplThread());
 
-    state.DidLeaveBeginFrame();
-    EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-    EXPECT_FALSE(state.BeginFrameNeededToDrawByImplThread());
-    state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-    EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+    EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+    EXPECT_FALSE(state.BeginFrameNeededByImplThread());
+    state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+    EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+    state.OnBeginFrameDeadline();
   }
 
   // If commit requested, begin a main frame.
   {
     StateMachine state(default_scheduler_settings);
     state.SetCommitState(SchedulerStateMachine::COMMIT_STATE_IDLE);
     state.SetCanStart();
     state.SetNeedsRedraw(false);
     state.SetVisible(true);
-    EXPECT_FALSE(state.BeginFrameNeededToDrawByImplThread());
+    EXPECT_FALSE(state.BeginFrameNeededByImplThread());
   }
 
   // Begin the frame, make sure needs_commit and commit_state update correctly.
   {
     StateMachine state(default_scheduler_settings);
     state.SetCanStart();
     state.UpdateState(state.NextAction());
     state.DidCreateAndInitializeOutputSurface();
     state.SetVisible(true);
     state.UpdateState(
         SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
     EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
               state.CommitState());
     EXPECT_FALSE(state.NeedsCommit());
     EXPECT_FALSE(state.BeginFrameNeededToDrawByImplThread());
   }
 }
 
 TEST(SchedulerStateMachineTest, TestSetForcedRedrawDoesNotSetsNormalRedraw) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
   state.SetCanDraw(true);
-  state.SetNeedsForcedRedraw();
+  state.SetNeedsForcedRedrawForReadback();
   EXPECT_FALSE(state.RedrawPending());
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
+  EXPECT_FALSE(state.BeginFrameNeededByImplThread());
 }
 
 TEST(SchedulerStateMachineTest,
      TestFailedDrawSetsNeedsCommitAndDoesNotDrawAgain) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
-  state.SetNeedsRedraw();
+  state.SetNeedsRedraw(true);
   EXPECT_TRUE(state.RedrawPending());
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
 
   // We're drawing now.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
   EXPECT_FALSE(state.RedrawPending());
   EXPECT_FALSE(state.CommitPending());
 
   // Failing the draw makes us require a commit.
   state.DidDrawIfPossibleCompleted(false);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-      state.NextAction());
-  state.UpdateState(
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
       SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   EXPECT_TRUE(state.RedrawPending());
   EXPECT_TRUE(state.CommitPending());
 }
 
 TEST(SchedulerStateMachineTest,
      TestsetNeedsRedrawDuringFailedDrawDoesNotRemoveNeedsRedraw) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
 
   state.SetVisible(true);
   state.SetCanDraw(true);
-  state.SetNeedsRedraw();
+  state.SetNeedsRedraw(true);
   EXPECT_TRUE(state.RedrawPending());
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
 
   // We're drawing now.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
   EXPECT_FALSE(state.RedrawPending());
   EXPECT_FALSE(state.CommitPending());
 
   // While still in the same begin frame callback on the main thread,
   // set needs redraw again. This should not redraw.
-  state.SetNeedsRedraw();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  state.SetNeedsRedraw(true);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Failing the draw makes us require a commit.
   state.DidDrawIfPossibleCompleted(false);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   EXPECT_TRUE(state.RedrawPending());
 }
 
 TEST(SchedulerStateMachineTest,
-     TestCommitAfterFailedDrawAllowsDrawInSameFrame) {
-  SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
-  state.SetCanStart();
-  state.UpdateState(state.NextAction());
-  state.DidCreateAndInitializeOutputSurface();
-  state.SetVisible(true);
-  state.SetCanDraw(true);
-
-  // Start a commit.
-  state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(
-      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
-  EXPECT_TRUE(state.CommitPending());
-
-  // Then initiate a draw.
-  state.SetNeedsRedraw();
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  EXPECT_TRUE(state.RedrawPending());
-
-  // Fail the draw.
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-  state.DidDrawIfPossibleCompleted(false);
-  EXPECT_TRUE(state.RedrawPending());
-  // But the commit is ongoing.
-  EXPECT_TRUE(state.CommitPending());
-
-  // Finish the commit.
-  state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_COMMIT);
-  EXPECT_TRUE(state.RedrawPending());
-
-  // And we should be allowed to draw again.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-}
-
-TEST(SchedulerStateMachineTest,
-     TestCommitAfterFailedAndSuccessfulDrawDoesNotAllowDrawInSameFrame) {
-  SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
-  state.SetCanStart();
-  state.UpdateState(state.NextAction());
-  state.DidCreateAndInitializeOutputSurface();
-  state.SetVisible(true);
-  state.SetCanDraw(true);
-
-  // Start a commit.
-  state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(
-      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
-  EXPECT_TRUE(state.CommitPending());
-
-  // Then initiate a draw.
-  state.SetNeedsRedraw();
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  EXPECT_TRUE(state.RedrawPending());
-
-  // Fail the draw.
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-  state.DidDrawIfPossibleCompleted(false);
-  EXPECT_TRUE(state.RedrawPending());
-  // But the commit is ongoing.
-  EXPECT_TRUE(state.CommitPending());
-
-  // Force a draw.
-  state.SetNeedsForcedRedraw();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
-
-  // Do the forced draw.
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_FORCED);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-  EXPECT_FALSE(state.RedrawPending());
-  // And the commit is still ongoing.
-  EXPECT_TRUE(state.CommitPending());
-
-  // Finish the commit.
-  state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_COMMIT);
-  EXPECT_TRUE(state.RedrawPending());
-
-  // And we should not be allowed to draw again in the same frame..
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-}
-
-TEST(SchedulerStateMachineTest,
      TestFailedDrawsWillEventuallyForceADrawAfterTheNextCommit) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
   state.SetMaximumNumberOfFailedDrawsBeforeDrawIsForced(1);
 
   // Start a commit.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
       SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
   EXPECT_TRUE(state.CommitPending());
 
   // Then initiate a draw.
-  state.SetNeedsRedraw();
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  EXPECT_TRUE(state.RedrawPending());
+  state.SetNeedsRedraw(true);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
 
   // Fail the draw.
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
   state.DidDrawIfPossibleCompleted(false);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
   EXPECT_TRUE(state.RedrawPending());
   // But the commit is ongoing.
   EXPECT_TRUE(state.CommitPending());
 
   // Finish the commit. Note, we should not yet be forcing a draw, but should
   // continue the commit as usual.
   state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
   EXPECT_TRUE(state.RedrawPending());
 
-  // The redraw should be forced in this case.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
+  // The redraw should be forced at the end of the next BeginFrame.
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_FORCED);
 }
 
 TEST(SchedulerStateMachineTest,
     TestFailedDrawIsRetriedInNextBeginFrameForImplThread) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Start a draw.
-  state.SetNeedsRedraw();
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
+  state.SetNeedsRedraw(true);
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
   EXPECT_TRUE(state.RedrawPending());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
 
-  // Fail the draw.
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  // Fail the draw
   state.DidDrawIfPossibleCompleted(false);
+  EXPECT_ACTION_UPDATE_STATE(
+    SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
   EXPECT_TRUE(state.RedrawPending());
 
   // We should not be trying to draw again now, but we have a commit pending.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
-  state.DidLeaveBeginFrame();
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-
-  // We should try to draw again in the next begin frame on the impl thread.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
+  // We should try to draw again at the end of the next BeginFrame on
+  // the impl thread.
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, TestDoestDrawTwiceInSameFrame) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
-  state.SetNeedsRedraw();
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
+  state.SetNeedsRedraw(true);
 
-  // While still in the same begin frame for the impl thread, set needs redraw
-  // again. This should not redraw.
-  state.SetNeedsRedraw();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  // Draw the first frame.
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  state.DidDrawIfPossibleCompleted(true);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  // Before the next begin frame for the impl thread, set needs redraw
+  // again. This should not redraw until the next begin frame.
+  state.SetNeedsRedraw(true);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Move to another frame. This should now draw.
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
   state.DidDrawIfPossibleCompleted(true);
-  state.DidLeaveBeginFrame();
-  EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
-  state.DidDrawIfPossibleCompleted(true);
-  EXPECT_FALSE(state.BeginFrameNeededToDrawByImplThread());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  EXPECT_FALSE(state.BeginFrameNeededByImplThread());
 }
 
 TEST(SchedulerStateMachineTest, TestNextActionDrawsOnBeginFrame) {
   SchedulerSettings default_scheduler_settings;
 
-  // When not in BeginFrame, or in BeginFrame but not visible,
+  // When not in BeginFrame deadline, or in BeginFrame deadline but not visible,
   // don't draw.
-  size_t num_commit_states =
-      sizeof(all_commit_states) / sizeof(SchedulerStateMachine::CommitState);
+  size_t num_commit_states = sizeof(all_commit_states) /
+      sizeof(SchedulerStateMachine::CommitState);
+  size_t num_begin_frame_states = sizeof(all_begin_frame_states) /
+      sizeof(SchedulerStateMachine::BeginFrameState);
   for (size_t i = 0; i < num_commit_states; ++i) {
-    for (size_t j = 0; j < 2; ++j) {
+    for (size_t j = 0; j < num_begin_frame_states; ++j) {
+      // We aren't testing forced draws here.
+      if (SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW ==
+          all_commit_states[i])
+        continue;
+
       StateMachine state(default_scheduler_settings);
       state.SetCanStart();
       state.UpdateState(state.NextAction());
       state.DidCreateAndInitializeOutputSurface();
       state.SetCommitState(all_commit_states[i]);
-      bool visible = j;
-      if (!visible) {
-        state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-        state.SetVisible(false);
-      } else {
-        state.SetVisible(true);
-      }
+      state.SetBeginFrameState(all_begin_frame_states[j]);
+      bool visible = (all_begin_frame_states[j] ==
+                      SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE);
+      state.SetVisible(visible);
 
       // Case 1: needs_commit=false
-      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE,
+      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
                 state.NextAction());
 
       // Case 2: needs_commit=true
       state.SetNeedsCommit();
-      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE,
+      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
                 state.NextAction());
     }
   }
 
-  // When in BeginFrame, or not in BeginFrame but needs_forced_dedraw
-  // set, should always draw except if you're ready to commit, in which case
-  // commit.
+  // When in BeginFrame deadline we should always draw for SetNeedsRedraw or
+  // SetNeedsForcedRedrawForReadback have been called... except if we're
+  // ready to commit, in which case we expect a commit first.
   for (size_t i = 0; i < num_commit_states; ++i) {
     for (size_t j = 0; j < 2; ++j) {
+      bool forced_draw_for_readback = j;
+      // Skip invalid states
+      if ((SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW ==
+           all_commit_states[i]) &&
+          !forced_draw_for_readback)
+        continue;
+
       StateMachine state(default_scheduler_settings);
       state.SetCanStart();
       state.UpdateState(state.NextAction());
       state.DidCreateAndInitializeOutputSurface();
       state.SetCanDraw(true);
       state.SetCommitState(all_commit_states[i]);
-      bool forced_draw = j;
-      if (!forced_draw) {
-        state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+      state.SetBeginFrameState(
+          SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE);
+      if (!forced_draw_for_readback) {
         state.SetNeedsRedraw(true);
         state.SetVisible(true);
       } else {
-        state.SetNeedsForcedRedraw(true);
+        state.SetNeedsForcedRedrawForReadback();
       }
 
       SchedulerStateMachine::Action expected_action;
-      if (all_commit_states[i] !=
+      if (all_commit_states[i] ==
           SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT) {
+        expected_action = SchedulerStateMachine::ACTION_COMMIT;
+      } else if (forced_draw_for_readback) {
+        if (all_commit_states[i] ==
+            SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW)
+          expected_action = SchedulerStateMachine::ACTION_DRAW_AND_READBACK;
+        else
+          expected_action = SchedulerStateMachine::ACTION_NONE;
+      } else {
         expected_action =
-            forced_draw ? SchedulerStateMachine::ACTION_DRAW_FORCED
-                        : SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE;
-      } else {
-        expected_action = SchedulerStateMachine::ACTION_COMMIT;
+            SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE;
       }
 
       // Case 1: needs_commit=false.
-      EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
+      EXPECT_EQ(state.BeginFrameNeededByImplThread(),
+                !forced_draw_for_readback);
       EXPECT_EQ(expected_action, state.NextAction());
 
       // Case 2: needs_commit=true.
       state.SetNeedsCommit();
-      EXPECT_TRUE(state.BeginFrameNeededToDrawByImplThread());
+      EXPECT_EQ(state.BeginFrameNeededByImplThread(),
+                !forced_draw_for_readback);
       EXPECT_EQ(expected_action, state.NextAction());
     }
   }
 }
 
 TEST(SchedulerStateMachineTest, TestNoCommitStatesRedrawWhenInvisible) {
   SchedulerSettings default_scheduler_settings;
 
   size_t num_commit_states =
       sizeof(all_commit_states) / sizeof(SchedulerStateMachine::CommitState);
   for (size_t i = 0; i < num_commit_states; ++i) {
     // There shouldn't be any drawing regardless of BeginFrame.
     for (size_t j = 0; j < 2; ++j) {
       StateMachine state(default_scheduler_settings);
       state.SetCanStart();
       state.UpdateState(state.NextAction());
       state.DidCreateAndInitializeOutputSurface();
       state.SetCommitState(all_commit_states[i]);
       state.SetVisible(false);
       state.SetNeedsRedraw(true);
-      state.SetNeedsForcedRedraw(false);
-      if (j == 1)
-        state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+      state.SetNeedsForcedRedrawForReadback();
+      if (j == 1) {
+        state.SetBeginFrameState(
+          SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE);
+      }
 
       // Case 1: needs_commit=false.
-      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE,
+      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
                 state.NextAction());
 
       // Case 2: needs_commit=true.
       state.SetNeedsCommit();
-      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE,
+      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
                 state.NextAction());
     }
   }
 }
 
 TEST(SchedulerStateMachineTest, TestCanRedraw_StopsDraw) {
   SchedulerSettings default_scheduler_settings;
 
   size_t num_commit_states =
       sizeof(all_commit_states) / sizeof(SchedulerStateMachine::CommitState);
   for (size_t i = 0; i < num_commit_states; ++i) {
     // There shouldn't be any drawing regardless of BeginFrame.
     for (size_t j = 0; j < 2; ++j) {
       StateMachine state(default_scheduler_settings);
       state.SetCanStart();
       state.UpdateState(state.NextAction());
       state.DidCreateAndInitializeOutputSurface();
       state.SetCommitState(all_commit_states[i]);
       state.SetVisible(false);
       state.SetNeedsRedraw(true);
-      state.SetNeedsForcedRedraw(false);
+      state.SetNeedsForcedRedrawForReadback();
       if (j == 1)
-        state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+        state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
 
       state.SetCanDraw(false);
-      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE,
+      EXPECT_NE(SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
                 state.NextAction());
     }
   }
 }
 
 TEST(SchedulerStateMachineTest,
      TestCanRedrawWithWaitingForFirstDrawMakesProgress) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetCommitState(
       SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW);
   state.SetNeedsCommit();
   state.SetNeedsRedraw(true);
   state.SetVisible(true);
   state.SetCanDraw(false);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, TestsetNeedsCommitIsNotLost) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetNeedsCommit();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
+  EXPECT_TRUE(state.BeginFrameNeededByImplThread());
+
   // Begin the frame.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState());
 
   // Now, while the frame is in progress, set another commit.
   state.SetNeedsCommit();
   EXPECT_TRUE(state.NeedsCommit());
 
   // Let the frame finish.
   state.FinishCommit();
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
             state.CommitState());
 
   // Expect to commit regardless of BeginFrame state.
-  state.DidLeaveBeginFrame();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_BEGIN_FRAME,
+            state.begin_frame_state());
   EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+
+  state.AdvanceBeginFrameStateWhenNoActionsRemain();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_DEADLINE_PENDING,
+            state.begin_frame_state());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
+
+  state.OnBeginFrameDeadline();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE,
+            state.begin_frame_state());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
+
+  state.AdvanceBeginFrameStateWhenNoActionsRemain();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_IDLE,
+            state.begin_frame_state());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
+
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_BEGIN_FRAME,
+            state.begin_frame_state());
   EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
 
   // Commit and make sure we draw on next BeginFrame
-  state.UpdateState(SchedulerStateMachine::ACTION_COMMIT);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
             state.CommitState());
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
   state.DidDrawIfPossibleCompleted(true);
 
-  // Verify that another commit will begin.
-  state.DidLeaveBeginFrame();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
+  // Verify that another commit will start immediately after draw.
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, TestFullCycle) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Start clean and set commit.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
 
   // Begin the frame.
-  state.UpdateState(
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
       SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState());
   EXPECT_FALSE(state.NeedsCommit());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Tell the scheduler the frame finished.
   state.FinishCommit();
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
             state.CommitState());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
 
   // Commit.
-  state.UpdateState(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
             state.CommitState());
   EXPECT_TRUE(state.NeedsRedraw());
 
-  // Expect to do nothing until BeginFrame.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  // Expect to do nothing until BeginFrame deadline
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
-  // At BeginFrame, draw.
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
+  // At BeginFrame deadline, draw.
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
   state.DidDrawIfPossibleCompleted(true);
-  state.DidLeaveBeginFrame();
 
   // Should be synchronized, no draw needed, no action needed.
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_IDLE, state.CommitState());
   EXPECT_FALSE(state.NeedsRedraw());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
 }
 
 TEST(SchedulerStateMachineTest, TestFullCycleWithCommitRequestInbetween) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Start clean and set commit.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
 
   // Begin the frame.
-  state.UpdateState(
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
       SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState());
   EXPECT_FALSE(state.NeedsCommit());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Request another commit while the commit is in flight.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Tell the scheduler the frame finished.
   state.FinishCommit();
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
             state.CommitState());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
 
-  // Commit.
-  state.UpdateState(SchedulerStateMachine::ACTION_COMMIT);
+  // First commit.
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
             state.CommitState());
   EXPECT_TRUE(state.NeedsRedraw());
 
-  // Expect to do nothing until BeginFrame.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  // Expect to do nothing until BeginFrame deadline.
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
-  // At BeginFrame, draw.
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE);
+  // At BeginFrame deadline, draw.
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
   state.DidDrawIfPossibleCompleted(true);
-  state.DidLeaveBeginFrame();
 
   // Should be synchronized, no draw needed, no action needed.
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_IDLE, state.CommitState());
   EXPECT_FALSE(state.NeedsRedraw());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
+
+  // Next BeginFrame should initiate second commit.
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
 }
 
 TEST(SchedulerStateMachineTest, TestRequestCommitInvisible) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, TestGoesInvisibleBeforeFinishCommit) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Start clean and set commit.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
 
   // Begin the frame while visible.
-  state.UpdateState(
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
       SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState());
   EXPECT_FALSE(state.NeedsCommit());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Become invisible and abort the main thread's begin frame.
   state.SetVisible(false);
   state.BeginFrameAbortedByMainThread();
 
-  // We should now be back in the idle state as if we didn't start a frame at
-  // all.
+  // We should now be back in the idle state as if we never started the frame.
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_IDLE, state.CommitState());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  // We shouldn't do anything on the BeginFrame deadline.
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Become visible again.
   state.SetVisible(true);
 
-  // We should be beginning a frame now.
+  // We should handle the aborted commit on the next BeginFrame.
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_IDLE, state.CommitState());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-
-  // Begin the frame.
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
 
   // We should be starting the commit now.
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, TestFirstContextCreation) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
-  EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION);
   state.DidCreateAndInitializeOutputSurface();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Check that the first init does not SetNeedsCommit.
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+
+  // Check that a needs commit initiates a BeginFrame to the main thread.
   state.SetNeedsCommit();
-  EXPECT_NE(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
 }
 
 TEST(SchedulerStateMachineTest, TestContextLostWhenCompletelyIdle) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
 
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   EXPECT_NE(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
   state.DidLoseOutputSurface();
 
   EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
   state.UpdateState(state.NextAction());
 
   // Once context recreation begins, nothing should happen.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Recreate the context.
   state.DidCreateAndInitializeOutputSurface();
 
   // When the context is recreated, we should begin a commit.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
 }
 
 TEST(SchedulerStateMachineTest,
      TestContextLostWhenIdleAndCommitRequestedWhileRecreating) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   EXPECT_NE(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
   state.DidLoseOutputSurface();
 
-  EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION);
 
   // Once context recreation begins, nothing should happen.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // While context is recreating, commits shouldn't begin.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Recreate the context
   state.DidCreateAndInitializeOutputSurface();
 
   // When the context is recreated, we should begin a commit
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.FinishCommit();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Once the context is recreated, whether we draw should be based on
   // SetCanDraw.
+  state.OnBeginFrameDeadline();
   state.SetNeedsRedraw(true);
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
+            state.NextAction());
   state.SetCanDraw(false);
   EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
   state.SetCanDraw(true);
-  state.DidLeaveBeginFrame();
+  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE,
+            state.NextAction());
 }
 
 TEST(SchedulerStateMachineTest, TestContextLostWhileCommitInProgress) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Get a commit in flight.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Set damage and expect a draw.
   state.SetNeedsRedraw(true);
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(state.NextAction());
-  state.DidLeaveBeginFrame();
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Cause a lost context while the begin frame is in flight
   // for the main thread.
   state.DidLoseOutputSurface();
 
   // Ask for another draw. Expect nothing happens.
   state.SetNeedsRedraw(true);
   EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
 
   // Finish the frame, and commit.
   state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
 
+  // We still attempt to draw when output surface is lost if we are waiting
+  // for the first draw to unblock the main thread.
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
             state.CommitState());
-
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
 
   // Expect to be told to begin context recreation, independent of
   // BeginFrame state.
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_IDLE,
+            state.begin_frame_state());
   EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
-  state.DidLeaveBeginFrame();
+
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_BEGIN_FRAME,
+            state.begin_frame_state());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
+            state.NextAction());
+
+  state.AdvanceBeginFrameStateWhenNoActionsRemain();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_DEADLINE_PENDING,
+            state.begin_frame_state());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
+            state.NextAction());
+
+  state.OnBeginFrameDeadline();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE,
+            state.begin_frame_state());
   EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
 }
 
 TEST(SchedulerStateMachineTest,
      TestContextLostWhileCommitInProgressAndAnotherCommitRequested) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Get a commit in flight.
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Set damage and expect a draw.
   state.SetNeedsRedraw(true);
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(state.NextAction());
-  state.DidLeaveBeginFrame();
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+    SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Cause a lost context while the begin frame is in flight
   // for the main thread.
   state.DidLoseOutputSurface();
 
   // Ask for another draw and also set needs commit. Expect nothing happens.
   state.SetNeedsRedraw(true);
   state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Finish the frame, and commit.
   state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
-  state.UpdateState(state.NextAction());
-
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_DRAW,
             state.CommitState());
-
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_IF_POSSIBLE, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
 
   // Expect to be told to begin context recreation, independent of
   // BeginFrame state
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_IDLE,
+            state.begin_frame_state());
   EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
-  state.DidLeaveBeginFrame();
+
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_BEGIN_FRAME,
+            state.begin_frame_state());
   EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
+
+  state.AdvanceBeginFrameStateWhenNoActionsRemain();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_DEADLINE_PENDING,
+            state.begin_frame_state());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
+            state.NextAction());
+
+  state.OnBeginFrameDeadline();
+  EXPECT_EQ(SchedulerStateMachine::BEGIN_FRAME_STATE_INSIDE_DEADLINE,
+            state.begin_frame_state());
+  EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
+            state.NextAction());
+
+  // After we get a new output surface, the commit flow should start.
+  state.DidCreateAndInitializeOutputSurface();
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+    SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.FinishCommit();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, TestFinishAllRenderingWhileContextLost) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Cause a lost context lost.
   state.DidLoseOutputSurface();
 
-  // Ask a forced redraw and verify it ocurrs.
-  state.SetNeedsForcedRedraw(true);
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
-  state.DidLeaveBeginFrame();
+  // Ask a forced redraw for readback and verify it ocurrs.
+  state.SetCommitState(
+      SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW);
+  state.SetNeedsForcedRedrawForReadback();
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_DRAW_AND_READBACK);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
-  // Clear the forced redraw bit.
-  state.SetNeedsForcedRedraw(false);
+  // Forced redraws for readbacks need to be followed by a new commit
+  // to replace the readback commit.
+  EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
+            state.CommitState());
+  state.FinishCommit();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE);
 
   // Expect to be told to begin context recreation, independent of
   // BeginFrame state
-  EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
-            state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_IDLE, state.CommitState());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION);
+
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Ask a forced redraw and verify it ocurrs.
-  state.SetNeedsForcedRedraw(true);
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
-  state.DidLeaveBeginFrame();
+  state.SetCommitState(
+      SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW);
+  state.SetNeedsForcedRedrawForReadback();
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
+  state.OnBeginFrameDeadline();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_SWAP_FORCED);
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, DontDrawBeforeCommitAfterLostOutputSurface) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   state.SetNeedsRedraw(true);
 
   // Cause a lost output surface, and restore it.
   state.DidLoseOutputSurface();
   EXPECT_EQ(SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION,
             state.NextAction());
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
 
   EXPECT_FALSE(state.RedrawPending());
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
   EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
             state.NextAction());
 }
 
 TEST(SchedulerStateMachineTest,
     TestSendBeginFrameToMainThreadWhenInvisibleAndForceCommit) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(false);
   state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
+  state.SetNeedsForcedCommitForReadback();
   EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
             state.NextAction());
 }
 
 TEST(SchedulerStateMachineTest,
     TestSendBeginFrameToMainThreadWhenCanStartFalseAndForceCommit) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetVisible(true);
   state.SetCanDraw(true);
   state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
+  state.SetNeedsForcedCommitForReadback();
   EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
             state.NextAction());
 }
 
 TEST(SchedulerStateMachineTest, TestFinishCommitWhenCommitInProgress) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
@@ skipping 13 matching lines @@
 
 TEST(SchedulerStateMachineTest, TestFinishCommitWhenForcedCommitInProgress) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(false);
   state.SetCommitState(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS);
   state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
+  state.SetNeedsForcedCommitForReadback();
 
+  // The commit for readback interupts the normal commit.
   state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
 
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW,
             state.CommitState());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_DRAW_AND_READBACK);
 
-  // If we are waiting for forced draw then we know a begin frame is already
-  // in flight for the main thread.
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
+  // When the readback interrupts the normal commit, we should not get
+  // another BeginFrame on the impl thread when the readback completes.
+  EXPECT_NE(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
+            state.NextAction());
+
+  // The normal commit can then proceed.
+  state.FinishCommit();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
 }
 
 TEST(SchedulerStateMachineTest, TestSendBeginFrameToMainThreadWhenContextLost) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
   state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
+  state.SetNeedsForcedCommitForReadback();
   state.DidLoseOutputSurface();
   EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
             state.NextAction());
 }
 
 TEST(SchedulerStateMachineTest, TestImmediateFinishCommit) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
-  // Schedule a forced frame, commit it, draw it.
+  // Schedule a readback, commit it, draw it.
   state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
-  state.UpdateState(state.NextAction());
+  state.SetNeedsForcedCommitForReadback();
+  EXPECT_ACTION_UPDATE_STATE(
+    SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
+
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
             state.CommitState());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
 
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW,
             state.CommitState());
 
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-  state.SetNeedsForcedRedraw(true);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_DRAW_AND_READBACK);
   state.DidDrawIfPossibleCompleted(true);
-  state.DidLeaveBeginFrame();
+
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Should be waiting for the normal begin frame from the main thread.
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState());
 }
 
 TEST(SchedulerStateMachineTest, TestImmediateFinishCommitDuringCommit) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   // Start a normal commit.
   state.SetNeedsCommit();
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
-  // Schedule a forced frame, commit it, draw it.
-  state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
-  state.UpdateState(state.NextAction());
+  // Schedule a readback, commit it, draw it.
+  state.SetNeedsForcedCommitForReadback();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   state.FinishCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
             state.CommitState());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
 
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW,
             state.CommitState());
-
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-  state.SetNeedsForcedRedraw(true);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_DRAW_AND_READBACK);
   state.DidDrawIfPossibleCompleted(true);
-  state.DidLeaveBeginFrame();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Should be waiting for the normal begin frame from the main thread.
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState()) << state.ToString();
 }
 
 TEST(SchedulerStateMachineTest,
     ImmediateBeginFrameAbortedByMainThreadWhileInvisible) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(true);
 
   state.SetNeedsCommit();
   state.UpdateState(state.NextAction());
 
   state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
-  state.UpdateState(state.NextAction());
+  state.SetNeedsForcedCommitForReadback();
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   state.FinishCommit();
 
-  EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
             state.CommitState());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_COMMIT);
 
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW,
             state.CommitState());
 
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-  state.SetNeedsForcedRedraw(true);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_DRAW_AND_READBACK);
   state.DidDrawIfPossibleCompleted(true);
-  state.DidLeaveBeginFrame();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 
   // Should be waiting for the main thread's begin frame.
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_FRAME_IN_PROGRESS,
             state.CommitState()) << state.ToString();
 
   // Become invisible and abort the main thread's begin frame.
   state.SetVisible(false);
   state.BeginFrameAbortedByMainThread();
 
   // Should be back in the idle state, but needing a commit.
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_IDLE, state.CommitState());
   EXPECT_TRUE(state.NeedsCommit());
 }
 
 TEST(SchedulerStateMachineTest, ImmediateFinishCommitWhileCantDraw) {
   SchedulerSettings default_scheduler_settings;
   StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetVisible(true);
   state.SetCanDraw(false);
 
   state.SetNeedsCommit();
   state.UpdateState(state.NextAction());
 
   state.SetNeedsCommit();
-  state.SetNeedsForcedCommit();
+  state.SetNeedsForcedCommitForReadback();
   state.UpdateState(state.NextAction());
   state.FinishCommit();
 
   EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_READY_TO_COMMIT,
             state.CommitState());
   state.UpdateState(state.NextAction());
 
   EXPECT_EQ(SchedulerStateMachine::COMMIT_STATE_WAITING_FOR_FIRST_FORCED_DRAW,
             state.CommitState());
 
-  state.DidEnterBeginFrame(BeginFrameArgs::CreateForTesting());
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-  state.SetNeedsForcedRedraw(true);
-  EXPECT_EQ(SchedulerStateMachine::ACTION_DRAW_FORCED, state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_DRAW_AND_READBACK);
   state.DidDrawIfPossibleCompleted(true);
-  state.DidLeaveBeginFrame();
+  EXPECT_ACTION_UPDATE_STATE(SchedulerStateMachine::ACTION_NONE);
 }
 
 TEST(SchedulerStateMachineTest, ReportIfNotDrawing) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
 
   state.SetCanDraw(true);
   state.SetVisible(true);
   EXPECT_FALSE(state.DrawSuspendedUntilCommit());
 
   state.SetCanDraw(false);
   state.SetVisible(true);
   EXPECT_TRUE(state.DrawSuspendedUntilCommit());
 
   state.SetCanDraw(true);
   state.SetVisible(false);
   EXPECT_TRUE(state.DrawSuspendedUntilCommit());
 
   state.SetCanDraw(false);
   state.SetVisible(false);
   EXPECT_TRUE(state.DrawSuspendedUntilCommit());
 
   state.SetCanDraw(true);
   state.SetVisible(true);
   EXPECT_FALSE(state.DrawSuspendedUntilCommit());
 }
 
 TEST(SchedulerStateMachineTest, ReportIfNotDrawingFromAcquiredTextures) {
   SchedulerSettings default_scheduler_settings;
-  SchedulerStateMachine state(default_scheduler_settings);
+  StateMachine state(default_scheduler_settings);
   state.SetCanStart();
   state.UpdateState(state.NextAction());
   state.DidCreateAndInitializeOutputSurface();
   state.SetCanDraw(true);
   state.SetVisible(true);
   EXPECT_FALSE(state.DrawSuspendedUntilCommit());
 
   state.SetMainThreadNeedsLayerTextures();
-  EXPECT_EQ(
-      SchedulerStateMachine::ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD,
-      state.NextAction());
-  state.UpdateState(state.NextAction());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_ACQUIRE_LAYER_TEXTURES_FOR_MAIN_THREAD);
+  EXPECT_TRUE(state.DrawSuspendedUntilCommit());
+
+  state.SetNeedsCommit();
+  state.OnBeginFrame(BeginFrameArgs::CreateForTesting());
+  EXPECT_ACTION_UPDATE_STATE(
+      SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD);
   EXPECT_TRUE(state.DrawSuspendedUntilCommit());
 
   EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
-
-  state.SetNeedsCommit();
-  EXPECT_EQ(SchedulerStateMachine::ACTION_SEND_BEGIN_FRAME_TO_MAIN_THREAD,
-            state.NextAction());
-
-  state.UpdateState(state.NextAction());
-  EXPECT_TRUE(state.DrawSuspendedUntilCommit());
-
-  EXPECT_EQ(SchedulerStateMachine::ACTION_NONE, state.NextAction());
 
   state.FinishCommit();
   EXPECT_TRUE(state.DrawSuspendedUntilCommit());
 
   EXPECT_EQ(SchedulerStateMachine::ACTION_COMMIT, state.NextAction());
 
   state.UpdateState(state.NextAction());
   EXPECT_FALSE(state.DrawSuspendedUntilCommit());
 }
 
 }  // namespace
 }  // namespace cc