Revert "Delete CC."

cc/scheduler/scheduler.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 <algorithm>
+
+#include "base/auto_reset.h"
+#include "base/logging.h"
+#include "base/profiler/scoped_tracker.h"
+#include "base/single_thread_task_runner.h"
+#include "base/trace_event/trace_event.h"
+#include "base/trace_event/trace_event_argument.h"
+#include "cc/debug/traced_value.h"
+#include "cc/scheduler/delay_based_time_source.h"
+#include "ui/gfx/frame_time.h"
+
+namespace cc {
+
+BeginFrameSource* SchedulerFrameSourcesConstructor::ConstructPrimaryFrameSource(
+    Scheduler* scheduler) {
+  if (scheduler->settings_.use_external_begin_frame_source) {
+    TRACE_EVENT1("cc",
+                 "Scheduler::Scheduler()",
+                 "PrimaryFrameSource",
+                 "ExternalBeginFrameSource");
+    DCHECK(scheduler->primary_frame_source_internal_)
+        << "Need external BeginFrameSource";
+    return scheduler->primary_frame_source_internal_.get();
+  } else {
+    TRACE_EVENT1("cc",
+                 "Scheduler::Scheduler()",
+                 "PrimaryFrameSource",
+                 "SyntheticBeginFrameSource");
+    scoped_ptr<SyntheticBeginFrameSource> synthetic_source =
+        SyntheticBeginFrameSource::Create(scheduler->task_runner_.get(),
+                                          scheduler->Now(),
+                                          BeginFrameArgs::DefaultInterval());
+
+    DCHECK(!scheduler->vsync_observer_);
+    scheduler->vsync_observer_ = synthetic_source.get();
+
+    DCHECK(!scheduler->primary_frame_source_internal_);
+    scheduler->primary_frame_source_internal_ = synthetic_source.Pass();
+    return scheduler->primary_frame_source_internal_.get();
+  }
+}
+
+BeginFrameSource*
+SchedulerFrameSourcesConstructor::ConstructBackgroundFrameSource(
+    Scheduler* scheduler) {
+  TRACE_EVENT1("cc",
+               "Scheduler::Scheduler()",
+               "BackgroundFrameSource",
+               "SyntheticBeginFrameSource");
+  DCHECK(!(scheduler->background_frame_source_internal_));
+  scheduler->background_frame_source_internal_ =
+      SyntheticBeginFrameSource::Create(
+          scheduler->task_runner_.get(), scheduler->Now(),
+          scheduler->settings_.background_frame_interval);
+  return scheduler->background_frame_source_internal_.get();
+}
+
+BeginFrameSource*
+SchedulerFrameSourcesConstructor::ConstructUnthrottledFrameSource(
+    Scheduler* scheduler) {
+  TRACE_EVENT1("cc", "Scheduler::Scheduler()", "UnthrottledFrameSource",
+               "BackToBackBeginFrameSource");
+  DCHECK(!scheduler->unthrottled_frame_source_internal_);
+  scheduler->unthrottled_frame_source_internal_ =
+      BackToBackBeginFrameSource::Create(scheduler->task_runner_.get());
+  return scheduler->unthrottled_frame_source_internal_.get();
+}
+
+Scheduler::Scheduler(
+    SchedulerClient* client,
+    const SchedulerSettings& scheduler_settings,
+    int layer_tree_host_id,
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+    scoped_ptr<BeginFrameSource> external_begin_frame_source,
+    SchedulerFrameSourcesConstructor* frame_sources_constructor)
+    : frame_source_(),
+      primary_frame_source_(NULL),
+      background_frame_source_(NULL),
+      primary_frame_source_internal_(external_begin_frame_source.Pass()),
+      background_frame_source_internal_(),
+      vsync_observer_(NULL),
+      throttle_frame_production_(scheduler_settings.throttle_frame_production),
+      settings_(scheduler_settings),
+      client_(client),
+      layer_tree_host_id_(layer_tree_host_id),
+      task_runner_(task_runner),
+      state_machine_(scheduler_settings),
+      inside_process_scheduled_actions_(false),
+      inside_action_(SchedulerStateMachine::ACTION_NONE),
+      weak_factory_(this) {
+  TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
+               "Scheduler::Scheduler",
+               "settings",
+               settings_.AsValue());
+  DCHECK(client_);
+  DCHECK(!state_machine_.BeginFrameNeeded());
+
+  begin_retro_frame_closure_ =
+      base::Bind(&Scheduler::BeginRetroFrame, weak_factory_.GetWeakPtr());
+  begin_impl_frame_deadline_closure_ = base::Bind(
+      &Scheduler::OnBeginImplFrameDeadline, weak_factory_.GetWeakPtr());
+  poll_for_draw_triggers_closure_ = base::Bind(
+      &Scheduler::PollForAnticipatedDrawTriggers, weak_factory_.GetWeakPtr());
+  advance_commit_state_closure_ = base::Bind(
+      &Scheduler::PollToAdvanceCommitState, weak_factory_.GetWeakPtr());
+
+  frame_source_ = BeginFrameSourceMultiplexer::Create();
+  frame_source_->AddObserver(this);
+
+  // Primary frame source
+  primary_frame_source_ =
+      frame_sources_constructor->ConstructPrimaryFrameSource(this);
+  frame_source_->AddSource(primary_frame_source_);
+  primary_frame_source_->SetClientReady();
+
+  // Background ticking frame source
+  background_frame_source_ =
+      frame_sources_constructor->ConstructBackgroundFrameSource(this);
+  frame_source_->AddSource(background_frame_source_);
+
+  // Unthrottled frame source
+  unthrottled_frame_source_ =
+      frame_sources_constructor->ConstructUnthrottledFrameSource(this);
+  frame_source_->AddSource(unthrottled_frame_source_);
+}
+
+Scheduler::~Scheduler() {
+  if (frame_source_->NeedsBeginFrames())
+    frame_source_->SetNeedsBeginFrames(false);
+}
+
+base::TimeTicks Scheduler::Now() const {
+  base::TimeTicks now = gfx::FrameTime::Now();
+  TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler.now"),
+               "Scheduler::Now",
+               "now",
+               now);
+  return now;
+}
+
+void Scheduler::CommitVSyncParameters(base::TimeTicks timebase,
+                                      base::TimeDelta interval) {
+  // TODO(brianderson): We should not be receiving 0 intervals.
+  if (interval == base::TimeDelta())
+    interval = BeginFrameArgs::DefaultInterval();
+
+  if (vsync_observer_)
+    vsync_observer_->OnUpdateVSyncParameters(timebase, interval);
+}
+
+void Scheduler::SetEstimatedParentDrawTime(base::TimeDelta draw_time) {
+  DCHECK_GE(draw_time.ToInternalValue(), 0);
+  estimated_parent_draw_time_ = draw_time;
+}
+
+void Scheduler::SetCanStart() {
+  state_machine_.SetCanStart();
+  ProcessScheduledActions();
+}
+
+void Scheduler::UpdateActiveFrameSource() {
+  if (state_machine_.visible()) {
+    if (throttle_frame_production_) {
+      frame_source_->SetActiveSource(primary_frame_source_);
+    } else {
+      frame_source_->SetActiveSource(unthrottled_frame_source_);
+    }
+  } else {
+    frame_source_->SetActiveSource(background_frame_source_);
+  }
+  ProcessScheduledActions();
+}
+
+void Scheduler::SetVisible(bool visible) {
+  state_machine_.SetVisible(visible);
+  UpdateActiveFrameSource();
+}
+
+void Scheduler::SetCanDraw(bool can_draw) {
+  state_machine_.SetCanDraw(can_draw);
+  ProcessScheduledActions();
+}
+
+void Scheduler::NotifyReadyToActivate() {
+  state_machine_.NotifyReadyToActivate();
+  ProcessScheduledActions();
+}
+
+void Scheduler::NotifyReadyToDraw() {
+  // Empty for now, until we take action based on the notification as part of
+  // crbugs 352894, 383157, 421923.
+}
+
+void Scheduler::SetThrottleFrameProduction(bool throttle) {
+  throttle_frame_production_ = throttle;
+  UpdateActiveFrameSource();
+}
+
+void Scheduler::SetNeedsCommit() {
+  state_machine_.SetNeedsCommit();
+  ProcessScheduledActions();
+}
+
+void Scheduler::SetNeedsRedraw() {
+  state_machine_.SetNeedsRedraw();
+  ProcessScheduledActions();
+}
+
+void Scheduler::SetNeedsAnimate() {
+  state_machine_.SetNeedsAnimate();
+  ProcessScheduledActions();
+}
+
+void Scheduler::SetNeedsPrepareTiles() {
+  DCHECK(!IsInsideAction(SchedulerStateMachine::ACTION_PREPARE_TILES));
+  state_machine_.SetNeedsPrepareTiles();
+  ProcessScheduledActions();
+}
+
+void Scheduler::SetMaxSwapsPending(int max) {
+  state_machine_.SetMaxSwapsPending(max);
+}
+
+void Scheduler::DidSwapBuffers() {
+  state_machine_.DidSwapBuffers();
+
+  // There is no need to call ProcessScheduledActions here because
+  // swapping should not trigger any new actions.
+  if (!inside_process_scheduled_actions_) {
+    DCHECK_EQ(state_machine_.NextAction(), SchedulerStateMachine::ACTION_NONE);
+  }
+}
+
+void Scheduler::DidSwapBuffersComplete() {
+  state_machine_.DidSwapBuffersComplete();
+  ProcessScheduledActions();
+}
+
+void Scheduler::SetImplLatencyTakesPriority(bool impl_latency_takes_priority) {
+  state_machine_.SetImplLatencyTakesPriority(impl_latency_takes_priority);
+  ProcessScheduledActions();
+}
+
+void Scheduler::NotifyReadyToCommit() {
+  TRACE_EVENT0("cc", "Scheduler::NotifyReadyToCommit");
+  state_machine_.NotifyReadyToCommit();
+  ProcessScheduledActions();
+}
+
+void Scheduler::BeginMainFrameAborted(CommitEarlyOutReason reason) {
+  TRACE_EVENT1("cc", "Scheduler::BeginMainFrameAborted", "reason",
+               CommitEarlyOutReasonToString(reason));
+  state_machine_.BeginMainFrameAborted(reason);
+  ProcessScheduledActions();
+}
+
+void Scheduler::DidPrepareTiles() {
+  state_machine_.DidPrepareTiles();
+}
+
+void Scheduler::DidLoseOutputSurface() {
+  TRACE_EVENT0("cc", "Scheduler::DidLoseOutputSurface");
+  begin_retro_frame_args_.clear();
+  begin_retro_frame_task_.Cancel();
+  state_machine_.DidLoseOutputSurface();
+  ProcessScheduledActions();
+}
+
+void Scheduler::DidCreateAndInitializeOutputSurface() {
+  TRACE_EVENT0("cc", "Scheduler::DidCreateAndInitializeOutputSurface");
+  DCHECK(!frame_source_->NeedsBeginFrames());
+  DCHECK(begin_impl_frame_deadline_task_.IsCancelled());
+  state_machine_.DidCreateAndInitializeOutputSurface();
+  ProcessScheduledActions();
+}
+
+void Scheduler::NotifyBeginMainFrameStarted() {
+  TRACE_EVENT0("cc", "Scheduler::NotifyBeginMainFrameStarted");
+  state_machine_.NotifyBeginMainFrameStarted();
+}
+
+base::TimeTicks Scheduler::AnticipatedDrawTime() const {
+  if (!frame_source_->NeedsBeginFrames() ||
+      begin_impl_frame_args_.interval <= base::TimeDelta())
+    return base::TimeTicks();
+
+  base::TimeTicks now = Now();
+  base::TimeTicks timebase = std::max(begin_impl_frame_args_.frame_time,
+                                      begin_impl_frame_args_.deadline);
+  int64 intervals = 1 + ((now - timebase) / begin_impl_frame_args_.interval);
+  return timebase + (begin_impl_frame_args_.interval * intervals);
+}
+
+base::TimeTicks Scheduler::LastBeginImplFrameTime() {
+  return begin_impl_frame_args_.frame_time;
+}
+
+void Scheduler::SetupNextBeginFrameIfNeeded() {
+  // Never call SetNeedsBeginFrames if the frame source already has the right
+  // value.
+  if (frame_source_->NeedsBeginFrames() != state_machine_.BeginFrameNeeded()) {
+    if (state_machine_.BeginFrameNeeded()) {
+      // Call SetNeedsBeginFrames(true) as soon as possible.
+      frame_source_->SetNeedsBeginFrames(true);
+    } else if (state_machine_.begin_impl_frame_state() ==
+               SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE) {
+      // Call SetNeedsBeginFrames(false) in between frames only.
+      frame_source_->SetNeedsBeginFrames(false);
+      client_->SendBeginMainFrameNotExpectedSoon();
+    }
+  }
+
+  PostBeginRetroFrameIfNeeded();
+}
+
+// We may need to poll when we can't rely on BeginFrame to advance certain
+// state or to avoid deadlock.
+void Scheduler::SetupPollingMechanisms() {
+  bool needs_advance_commit_state_timer = false;
+  // Setup PollForAnticipatedDrawTriggers if we need to monitor state but
+  // aren't expecting any more BeginFrames. This should only be needed by
+  // the synchronous compositor when BeginFrameNeeded is false.
+  if (state_machine_.ShouldPollForAnticipatedDrawTriggers()) {
+    DCHECK(!state_machine_.SupportsProactiveBeginFrame());
+    if (poll_for_draw_triggers_task_.IsCancelled()) {
+      poll_for_draw_triggers_task_.Reset(poll_for_draw_triggers_closure_);
+      base::TimeDelta delay = begin_impl_frame_args_.IsValid()
+                                  ? begin_impl_frame_args_.interval
+                                  : BeginFrameArgs::DefaultInterval();
+      task_runner_->PostDelayedTask(
+          FROM_HERE, poll_for_draw_triggers_task_.callback(), delay);
+    }
+  } else {
+    poll_for_draw_triggers_task_.Cancel();
+
+    // At this point we'd prefer to advance through the commit flow by
+    // drawing a frame, however it's possible that the frame rate controller
+    // will not give us a BeginFrame until the commit completes.  See
+    // crbug.com/317430 for an example of a swap ack being held on commit. Thus
+    // we set a repeating timer to poll on ProcessScheduledActions until we
+    // successfully reach BeginFrame. Synchronous compositor does not use
+    // frame rate controller or have the circular wait in the bug.
+    if (IsBeginMainFrameSentOrStarted() &&
+        !settings_.using_synchronous_renderer_compositor) {
+      needs_advance_commit_state_timer = true;
+    }
+  }
+
+  if (needs_advance_commit_state_timer) {
+    if (advance_commit_state_task_.IsCancelled() &&
+        begin_impl_frame_args_.IsValid()) {
+      // Since we'd rather get a BeginImplFrame by the normal mechanism, we
+      // set the interval to twice the interval from the previous frame.
+      advance_commit_state_task_.Reset(advance_commit_state_closure_);
+      task_runner_->PostDelayedTask(FROM_HERE,
+                                    advance_commit_state_task_.callback(),
+                                    begin_impl_frame_args_.interval * 2);
+    }
+  } else {
+    advance_commit_state_task_.Cancel();
+  }
+}
+
+// BeginFrame is the mechanism that tells us that now is a good time to start
+// making a frame. Usually this means that user input for the frame is complete.
+// If the scheduler is busy, we queue the BeginFrame to be handled later as
+// a BeginRetroFrame.
+bool Scheduler::OnBeginFrameMixInDelegate(const BeginFrameArgs& args) {
+  TRACE_EVENT1("cc,benchmark", "Scheduler::BeginFrame", "args", args.AsValue());
+
+  // Deliver BeginFrames to children.
+  if (state_machine_.children_need_begin_frames()) {
+    BeginFrameArgs adjusted_args_for_children(args);
+    // Adjust a deadline for child schedulers.
+    // TODO(simonhong): Once we have commitless update, we can get rid of
+    // BeginMainFrameToCommitDurationEstimate() +
+    // CommitToActivateDurationEstimate().
+    adjusted_args_for_children.deadline -=
+        (client_->BeginMainFrameToCommitDurationEstimate() +
+         client_->CommitToActivateDurationEstimate() +
+         client_->DrawDurationEstimate() + EstimatedParentDrawTime());
+    client_->SendBeginFramesToChildren(adjusted_args_for_children);
+  }
+
+  // We have just called SetNeedsBeginFrame(true) and the BeginFrameSource has
+  // sent us the last BeginFrame we have missed. As we might not be able to
+  // actually make rendering for this call, handle it like a "retro frame".
+  // TODO(brainderson): Add a test for this functionality ASAP!
+  if (args.type == BeginFrameArgs::MISSED) {
+    begin_retro_frame_args_.push_back(args);
+    PostBeginRetroFrameIfNeeded();
+    return true;
+  }
+
+  BeginFrameArgs adjusted_args(args);
+  adjusted_args.deadline -= EstimatedParentDrawTime();
+
+  bool should_defer_begin_frame;
+  if (settings_.using_synchronous_renderer_compositor) {
+    should_defer_begin_frame = false;
+  } else {
+    should_defer_begin_frame =
+        !begin_retro_frame_args_.empty() ||
+        !begin_retro_frame_task_.IsCancelled() ||
+        !frame_source_->NeedsBeginFrames() ||
+        (state_machine_.begin_impl_frame_state() !=
+         SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
+  }
+
+  if (should_defer_begin_frame) {
+    begin_retro_frame_args_.push_back(adjusted_args);
+    TRACE_EVENT_INSTANT0(
+        "cc", "Scheduler::BeginFrame deferred", TRACE_EVENT_SCOPE_THREAD);
+    // Queuing the frame counts as "using it", so we need to return true.
+  } else {
+    BeginImplFrame(adjusted_args);
+  }
+  return true;
+}
+
+void Scheduler::SetChildrenNeedBeginFrames(bool children_need_begin_frames) {
+  state_machine_.SetChildrenNeedBeginFrames(children_need_begin_frames);
+  ProcessScheduledActions();
+}
+
+// BeginRetroFrame is called for BeginFrames that we've deferred because
+// the scheduler was in the middle of processing a previous BeginFrame.
+void Scheduler::BeginRetroFrame() {
+  TRACE_EVENT0("cc,benchmark", "Scheduler::BeginRetroFrame");
+  DCHECK(!settings_.using_synchronous_renderer_compositor);
+  DCHECK(!begin_retro_frame_args_.empty());
+  DCHECK(!begin_retro_frame_task_.IsCancelled());
+  DCHECK_EQ(state_machine_.begin_impl_frame_state(),
+            SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
+
+  begin_retro_frame_task_.Cancel();
+
+  // Discard expired BeginRetroFrames
+  // Today, we should always end up with at most one un-expired BeginRetroFrame
+  // because deadlines will not be greater than the next frame time. We don't
+  // DCHECK though because some systems don't always have monotonic timestamps.
+  // TODO(brianderson): In the future, long deadlines could result in us not
+  // draining the queue if we don't catch up. If we consistently can't catch
+  // up, our fallback should be to lower our frame rate.
+  base::TimeTicks now = Now();
+
+  while (!begin_retro_frame_args_.empty()) {
+    const BeginFrameArgs& args = begin_retro_frame_args_.front();
+    base::TimeTicks expiration_time = args.frame_time + args.interval;
+    if (now <= expiration_time)
+      break;
+    TRACE_EVENT_INSTANT2(
+        "cc", "Scheduler::BeginRetroFrame discarding", TRACE_EVENT_SCOPE_THREAD,
+        "expiration_time - now", (expiration_time - now).InMillisecondsF(),
+        "BeginFrameArgs", begin_retro_frame_args_.front().AsValue());
+    begin_retro_frame_args_.pop_front();
+    frame_source_->DidFinishFrame(begin_retro_frame_args_.size());
+  }
+
+  if (begin_retro_frame_args_.empty()) {
+    TRACE_EVENT_INSTANT0("cc",
+                         "Scheduler::BeginRetroFrames all expired",
+                         TRACE_EVENT_SCOPE_THREAD);
+  } else {
+    BeginFrameArgs front = begin_retro_frame_args_.front();
+    begin_retro_frame_args_.pop_front();
+    BeginImplFrame(front);
+  }
+}
+
+// There could be a race between the posted BeginRetroFrame and a new
+// BeginFrame arriving via the normal mechanism. Scheduler::BeginFrame
+// will check if there is a pending BeginRetroFrame to ensure we handle
+// BeginFrames in FIFO order.
+void Scheduler::PostBeginRetroFrameIfNeeded() {
+  TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
+               "Scheduler::PostBeginRetroFrameIfNeeded",
+               "state",
+               AsValue());
+  if (!frame_source_->NeedsBeginFrames())
+    return;
+
+  if (begin_retro_frame_args_.empty() || !begin_retro_frame_task_.IsCancelled())
+    return;
+
+  // begin_retro_frame_args_ should always be empty for the
+  // synchronous compositor.
+  DCHECK(!settings_.using_synchronous_renderer_compositor);
+
+  if (state_machine_.begin_impl_frame_state() !=
+      SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE)
+    return;
+
+  begin_retro_frame_task_.Reset(begin_retro_frame_closure_);
+
+  task_runner_->PostTask(FROM_HERE, begin_retro_frame_task_.callback());
+}
+
+// BeginImplFrame starts a compositor frame that will wait up until a deadline
+// for a BeginMainFrame+activation to complete before it times out and draws
+// any asynchronous animation and scroll/pinch updates.
+void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
+  bool main_thread_is_in_high_latency_mode =
+      state_machine_.MainThreadIsInHighLatencyMode();
+  TRACE_EVENT2("cc,benchmark",
+               "Scheduler::BeginImplFrame",
+               "args",
+               args.AsValue(),
+               "main_thread_is_high_latency",
+               main_thread_is_in_high_latency_mode);
+  TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
+                 "MainThreadLatency",
+                 main_thread_is_in_high_latency_mode);
+  DCHECK_EQ(state_machine_.begin_impl_frame_state(),
+            SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
+  DCHECK(state_machine_.HasInitializedOutputSurface());
+
+  advance_commit_state_task_.Cancel();
+
+  begin_impl_frame_args_ = args;
+  begin_impl_frame_args_.deadline -= client_->DrawDurationEstimate();
+
+  if (!state_machine_.impl_latency_takes_priority() &&
+      main_thread_is_in_high_latency_mode &&
+      CanCommitAndActivateBeforeDeadline()) {
+    state_machine_.SetSkipNextBeginMainFrameToReduceLatency();
+  }
+
+  state_machine_.OnBeginImplFrame();
+  client_->WillBeginImplFrame(begin_impl_frame_args_);
+
+  ProcessScheduledActions();
+
+  state_machine_.OnBeginImplFrameDeadlinePending();
+
+  if (settings_.using_synchronous_renderer_compositor) {
+    // The synchronous renderer compositor has to make its GL calls
+    // within this call.
+    // TODO(brianderson): Have the OutputSurface initiate the deadline tasks
+    // so the synchronous renderer compositor can take advantage of splitting
+    // up the BeginImplFrame and deadline as well.
+    OnBeginImplFrameDeadline();
+  } else {
+    ScheduleBeginImplFrameDeadline();
+  }
+}
+
+void Scheduler::ScheduleBeginImplFrameDeadline() {
+  // The synchronous compositor does not post a deadline task.
+  DCHECK(!settings_.using_synchronous_renderer_compositor);
+
+  begin_impl_frame_deadline_task_.Cancel();
+  begin_impl_frame_deadline_task_.Reset(begin_impl_frame_deadline_closure_);
+
+  begin_impl_frame_deadline_mode_ =
+      state_machine_.CurrentBeginImplFrameDeadlineMode();
+
+  base::TimeTicks deadline;
+  switch (begin_impl_frame_deadline_mode_) {
+    case SchedulerStateMachine::BEGIN_IMPL_FRAME_DEADLINE_MODE_IMMEDIATE:
+      // We are ready to draw a new active tree immediately.
+      // We don't use Now() here because it's somewhat expensive to call.
+      deadline = base::TimeTicks();
+      break;
+    case SchedulerStateMachine::BEGIN_IMPL_FRAME_DEADLINE_MODE_REGULAR:
+      // We are animating on the impl thread but we can wait for some time.
+      deadline = begin_impl_frame_args_.deadline;
+      break;
+    case SchedulerStateMachine::BEGIN_IMPL_FRAME_DEADLINE_MODE_LATE:
+      // We are blocked for one reason or another and we should wait.
+      // TODO(brianderson): Handle long deadlines (that are past the next
+      // frame's frame time) properly instead of using this hack.
+      deadline =
+          begin_impl_frame_args_.frame_time + begin_impl_frame_args_.interval;
+      break;
+  }
+
+  TRACE_EVENT1(
+      "cc", "Scheduler::ScheduleBeginImplFrameDeadline", "deadline", deadline);
+
+  base::TimeDelta delta = deadline - Now();
+  if (delta <= base::TimeDelta())
+    delta = base::TimeDelta();
+  task_runner_->PostDelayedTask(
+      FROM_HERE, begin_impl_frame_deadline_task_.callback(), delta);
+}
+
+void Scheduler::RescheduleBeginImplFrameDeadlineIfNeeded() {
+  if (settings_.using_synchronous_renderer_compositor)
+    return;
+
+  if (state_machine_.begin_impl_frame_state() !=
+      SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME)
+    return;
+
+  if (begin_impl_frame_deadline_mode_ !=
+      state_machine_.CurrentBeginImplFrameDeadlineMode())
+    ScheduleBeginImplFrameDeadline();
+}
+
+void Scheduler::OnBeginImplFrameDeadline() {
+  TRACE_EVENT0("cc,benchmark", "Scheduler::OnBeginImplFrameDeadline");
+  begin_impl_frame_deadline_task_.Cancel();
+  // We split the deadline actions up into two phases so the state machine
+  // has a chance to trigger actions that should occur durring and after
+  // the deadline separately. For example:
+  // * Sending the BeginMainFrame will not occur after the deadline in
+  //     order to wait for more user-input before starting the next commit.
+  // * Creating a new OuputSurface will not occur during the deadline in
+  //     order to allow the state machine to "settle" first.
+
+  // TODO(robliao): Remove ScopedTracker below once crbug.com/461509 is fixed.
+  tracked_objects::ScopedTracker tracking_profile1(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "461509 Scheduler::OnBeginImplFrameDeadline1"));
+  state_machine_.OnBeginImplFrameDeadline();
+  ProcessScheduledActions();
+  state_machine_.OnBeginImplFrameIdle();
+  ProcessScheduledActions();
+
+  client_->DidBeginImplFrameDeadline();
+  frame_source_->DidFinishFrame(begin_retro_frame_args_.size());
+}
+
+void Scheduler::PollForAnticipatedDrawTriggers() {
+  TRACE_EVENT0("cc", "Scheduler::PollForAnticipatedDrawTriggers");
+  poll_for_draw_triggers_task_.Cancel();
+  state_machine_.DidEnterPollForAnticipatedDrawTriggers();
+  ProcessScheduledActions();
+  state_machine_.DidLeavePollForAnticipatedDrawTriggers();
+}
+
+void Scheduler::PollToAdvanceCommitState() {
+  TRACE_EVENT0("cc", "Scheduler::PollToAdvanceCommitState");
+  advance_commit_state_task_.Cancel();
+  ProcessScheduledActions();
+}
+
+void Scheduler::DrawAndSwapIfPossible() {
+  DrawResult result = client_->ScheduledActionDrawAndSwapIfPossible();
+  state_machine_.DidDrawIfPossibleCompleted(result);
+}
+
+void Scheduler::SetDeferCommits(bool defer_commits) {
+  TRACE_EVENT1("cc", "Scheduler::SetDeferCommits",
+                "defer_commits",
+                defer_commits);
+  state_machine_.SetDeferCommits(defer_commits);
+  ProcessScheduledActions();
+}
+
+void Scheduler::ProcessScheduledActions() {
+  // We do not allow ProcessScheduledActions to be recursive.
+  // The top-level call will iteratively execute the next action for us anyway.
+  if (inside_process_scheduled_actions_)
+    return;
+
+  base::AutoReset<bool> mark_inside(&inside_process_scheduled_actions_, true);
+
+  SchedulerStateMachine::Action action;
+  do {
+    action = state_machine_.NextAction();
+    TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
+                 "SchedulerStateMachine",
+                 "state",
+                 AsValue());
+    VLOG(2) << "Scheduler::ProcessScheduledActions: "
+            << SchedulerStateMachine::ActionToString(action) << " "
+            << state_machine_.GetStatesForDebugging();
+    state_machine_.UpdateState(action);
+    base::AutoReset<SchedulerStateMachine::Action>
+        mark_inside_action(&inside_action_, action);
+    switch (action) {
+      case SchedulerStateMachine::ACTION_NONE:
+        break;
+      case SchedulerStateMachine::ACTION_ANIMATE:
+        client_->ScheduledActionAnimate();
+        break;
+      case SchedulerStateMachine::ACTION_SEND_BEGIN_MAIN_FRAME:
+        client_->ScheduledActionSendBeginMainFrame();
+        break;
+      case SchedulerStateMachine::ACTION_COMMIT: {
+        // TODO(robliao): Remove ScopedTracker below once crbug.com/461509 is
+        // fixed.
+        tracked_objects::ScopedTracker tracking_profile4(
+            FROM_HERE_WITH_EXPLICIT_FUNCTION(
+                "461509 Scheduler::ProcessScheduledActions4"));
+        client_->ScheduledActionCommit();
+        break;
+      }
+      case SchedulerStateMachine::ACTION_ACTIVATE_SYNC_TREE:
+        client_->ScheduledActionActivateSyncTree();
+        break;
+      case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_IF_POSSIBLE: {
+        // TODO(robliao): Remove ScopedTracker below once crbug.com/461509 is
+        // fixed.
+        tracked_objects::ScopedTracker tracking_profile6(
+            FROM_HERE_WITH_EXPLICIT_FUNCTION(
+                "461509 Scheduler::ProcessScheduledActions6"));
+        DrawAndSwapIfPossible();
+        break;
+      }
+      case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_FORCED:
+        client_->ScheduledActionDrawAndSwapForced();
+        break;
+      case SchedulerStateMachine::ACTION_DRAW_AND_SWAP_ABORT:
+        // No action is actually performed, but this allows the state machine to
+        // advance out of its waiting to draw state without actually drawing.
+        break;
+      case SchedulerStateMachine::ACTION_BEGIN_OUTPUT_SURFACE_CREATION:
+        client_->ScheduledActionBeginOutputSurfaceCreation();
+        break;
+      case SchedulerStateMachine::ACTION_PREPARE_TILES:
+        client_->ScheduledActionPrepareTiles();
+        break;
+    }
+  } while (action != SchedulerStateMachine::ACTION_NONE);
+
+  SetupPollingMechanisms();
+
+  client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
+
+  RescheduleBeginImplFrameDeadlineIfNeeded();
+
+  SetupNextBeginFrameIfNeeded();
+}
+
+scoped_refptr<base::trace_event::ConvertableToTraceFormat> Scheduler::AsValue()
+    const {
+  scoped_refptr<base::trace_event::TracedValue> state =
+      new base::trace_event::TracedValue();
+  AsValueInto(state.get());
+  return state;
+}
+
+void Scheduler::AsValueInto(base::trace_event::TracedValue* state) const {
+  state->BeginDictionary("state_machine");
+  state_machine_.AsValueInto(state);
+  state->EndDictionary();
+
+  // Only trace frame sources when explicitly enabled - http://crbug.com/420607
+  bool frame_tracing_enabled = false;
+  TRACE_EVENT_CATEGORY_GROUP_ENABLED(
+      TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler.frames"),
+      &frame_tracing_enabled);
+  if (frame_tracing_enabled) {
+    state->BeginDictionary("frame_source_");
+    frame_source_->AsValueInto(state);
+    state->EndDictionary();
+  }
+
+  state->BeginDictionary("scheduler_state");
+  state->SetDouble("time_until_anticipated_draw_time_ms",
+                   (AnticipatedDrawTime() - Now()).InMillisecondsF());
+  state->SetDouble("estimated_parent_draw_time_ms",
+                   estimated_parent_draw_time_.InMillisecondsF());
+  state->SetBoolean("last_set_needs_begin_frame_",
+                    frame_source_->NeedsBeginFrames());
+  state->SetInteger("begin_retro_frame_args_", begin_retro_frame_args_.size());
+  state->SetBoolean("begin_retro_frame_task_",
+                    !begin_retro_frame_task_.IsCancelled());
+  state->SetBoolean("begin_impl_frame_deadline_task_",
+                    !begin_impl_frame_deadline_task_.IsCancelled());
+  state->SetBoolean("poll_for_draw_triggers_task_",
+                    !poll_for_draw_triggers_task_.IsCancelled());
+  state->SetBoolean("advance_commit_state_task_",
+                    !advance_commit_state_task_.IsCancelled());
+  state->BeginDictionary("begin_impl_frame_args");
+  begin_impl_frame_args_.AsValueInto(state);
+  state->EndDictionary();
+
+  base::TimeTicks now = Now();
+  base::TimeTicks frame_time = begin_impl_frame_args_.frame_time;
+  base::TimeTicks deadline = begin_impl_frame_args_.deadline;
+  base::TimeDelta interval = begin_impl_frame_args_.interval;
+  state->BeginDictionary("major_timestamps_in_ms");
+  state->SetDouble("0_interval", interval.InMillisecondsF());
+  state->SetDouble("1_now_to_deadline", (deadline - now).InMillisecondsF());
+  state->SetDouble("2_frame_time_to_now", (now - frame_time).InMillisecondsF());
+  state->SetDouble("3_frame_time_to_deadline",
+                   (deadline - frame_time).InMillisecondsF());
+  state->SetDouble("4_now", (now - base::TimeTicks()).InMillisecondsF());
+  state->SetDouble("5_frame_time",
+                   (frame_time - base::TimeTicks()).InMillisecondsF());
+  state->SetDouble("6_deadline",
+                   (deadline - base::TimeTicks()).InMillisecondsF());
+  state->EndDictionary();
+
+  state->EndDictionary();
+
+  state->BeginDictionary("client_state");
+  state->SetDouble("draw_duration_estimate_ms",
+                   client_->DrawDurationEstimate().InMillisecondsF());
+  state->SetDouble(
+      "begin_main_frame_to_commit_duration_estimate_ms",
+      client_->BeginMainFrameToCommitDurationEstimate().InMillisecondsF());
+  state->SetDouble(
+      "commit_to_activate_duration_estimate_ms",
+      client_->CommitToActivateDurationEstimate().InMillisecondsF());
+  state->EndDictionary();
+}
+
+bool Scheduler::CanCommitAndActivateBeforeDeadline() const {
+  // Check if the main thread computation and commit can be finished before the
+  // impl thread's deadline.
+  base::TimeTicks estimated_draw_time =
+      begin_impl_frame_args_.frame_time +
+      client_->BeginMainFrameToCommitDurationEstimate() +
+      client_->CommitToActivateDurationEstimate();
+
+  TRACE_EVENT2(
+      TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
+      "CanCommitAndActivateBeforeDeadline",
+      "time_left_after_drawing_ms",
+      (begin_impl_frame_args_.deadline - estimated_draw_time).InMillisecondsF(),
+      "state",
+      AsValue());
+
+  return estimated_draw_time < begin_impl_frame_args_.deadline;
+}
+
+bool Scheduler::IsBeginMainFrameSentOrStarted() const {
+  return (state_machine_.commit_state() ==
+              SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_SENT ||
+          state_machine_.commit_state() ==
+              SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_STARTED);
+}
+
+}  // namespace cc