cc: Make scheduling be driven by vsync for android webview.

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index ad5a6380ba2e655cf5592cc835586dab7e57939c..fc82b26af731984e0f4864131fe5931120c7555a 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -94,6 +94,8 @@ Scheduler::Scheduler(
       client_(client),
       layer_tree_host_id_(layer_tree_host_id),
       task_runner_(task_runner),
+      begin_impl_frame_deadline_mode_(
+          SchedulerStateMachine::BEGIN_IMPL_FRAME_DEADLINE_MODE_NONE),
       state_machine_(scheduler_settings),
       inside_process_scheduled_actions_(false),
       inside_action_(SchedulerStateMachine::ACTION_NONE),
@@ -109,8 +111,6 @@ Scheduler::Scheduler(
       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());
 
@@ -337,37 +337,15 @@ void Scheduler::SetupNextBeginFrameIfNeeded() {
 // 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) {
+  // 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) {
     if (advance_commit_state_task_.IsCancelled() &&
         begin_impl_frame_args_.IsValid()) {
       // Since we'd rather get a BeginImplFrame by the normal mechanism, we
@@ -406,6 +384,11 @@ bool Scheduler::OnBeginFrameMixInDelegate(const BeginFrameArgs& args) {
   BeginFrameArgs adjusted_args(args);
   adjusted_args.deadline -= EstimatedParentDrawTime();
 
+  if (settings_.using_synchronous_renderer_compositor) {
+    BeginImplFrameSynchronous(adjusted_args);
+    return true;
+  }
+
   // 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".
@@ -416,17 +399,12 @@ bool Scheduler::OnBeginFrameMixInDelegate(const BeginFrameArgs& args) {
     return true;
   }
 
-  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);
-  }
+  bool 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);
@@ -434,7 +412,7 @@ bool Scheduler::OnBeginFrameMixInDelegate(const BeginFrameArgs& args) {
         "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);
+    BeginImplFrameWithDeadline(adjusted_args);
   }
   return true;
 }
@@ -450,6 +428,19 @@ void Scheduler::SetAuthoritativeVSyncInterval(const base::TimeDelta& interval) {
     vsync_observer_->OnUpdateVSyncParameters(last_vsync_timebase_, interval);
 }
 
+void Scheduler::OnDrawForOutputSurface() {
+  DCHECK(settings_.using_synchronous_renderer_compositor);
+  DCHECK_EQ(state_machine_.begin_impl_frame_state(),
+            SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
+  DCHECK(!BeginImplFrameDeadlinePending());
+
+  state_machine_.OnBeginImplFrameDeadline();
+  ProcessScheduledActions();
+
+  state_machine_.OnBeginImplFrameIdle();
+  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() {
@@ -491,7 +482,7 @@ void Scheduler::BeginRetroFrame() {
   } else {
     BeginFrameArgs front = begin_retro_frame_args_.front();
     begin_retro_frame_args_.pop_front();
-    BeginImplFrame(front);
+    BeginImplFrameWithDeadline(front);
   }
 }
 
@@ -523,6 +514,27 @@ void Scheduler::PostBeginRetroFrameIfNeeded() {
   task_runner_->PostTask(FROM_HERE, begin_retro_frame_task_.callback());
 }
 
+void Scheduler::BeginImplFrameWithDeadline(const BeginFrameArgs& args) {
+  BeginImplFrame(args);
+
+  // The deadline will be scheduled in ProcessScheduledActions.
+  state_machine_.OnBeginImplFrameDeadlinePending();
+  ProcessScheduledActions();
+}
+
+void Scheduler::BeginImplFrameSynchronous(const BeginFrameArgs& args) {
+  BeginImplFrame(args);
+  FinishImplFrame();
+}
+
+void Scheduler::FinishImplFrame() {
+  state_machine_.OnBeginImplFrameIdle();
+  ProcessScheduledActions();
+
+  client_->DidBeginImplFrameDeadline();
+  frame_source_->DidFinishFrame(begin_retro_frame_args_.size());
+}
+
 // 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.
@@ -540,6 +552,7 @@ void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
                  main_thread_is_in_high_latency_mode);
   DCHECK_EQ(state_machine_.begin_impl_frame_state(),
             SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
+  DCHECK(!BeginImplFrameDeadlinePending());
   DCHECK(state_machine_.HasInitializedOutputSurface());
 
   advance_commit_state_task_.Cancel();
@@ -558,19 +571,6 @@ void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
   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() {
@@ -585,6 +585,9 @@ void Scheduler::ScheduleBeginImplFrameDeadline() {
 
   base::TimeTicks deadline;
   switch (begin_impl_frame_deadline_mode_) {
+    case SchedulerStateMachine::BEGIN_IMPL_FRAME_DEADLINE_MODE_NONE:
+      // No deadline.
+      return;
     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.
@@ -610,17 +613,17 @@ void Scheduler::ScheduleBeginImplFrameDeadline() {
       return;
   }
 
-  TRACE_EVENT1(
-      "cc", "Scheduler::ScheduleBeginImplFrameDeadline", "deadline", deadline);
+  TRACE_EVENT2("cc", "Scheduler::ScheduleBeginImplFrameDeadline", "mode",
+               SchedulerStateMachine::BeginImplFrameDeadlineModeToString(
+                   begin_impl_frame_deadline_mode_),
+               "deadline", deadline);
 
-  base::TimeDelta delta = deadline - Now();
-  if (delta <= base::TimeDelta())
-    delta = base::TimeDelta();
+  base::TimeDelta delta = std::max(deadline - Now(), base::TimeDelta());
   task_runner_->PostDelayedTask(
       FROM_HERE, begin_impl_frame_deadline_task_.callback(), delta);
 }
 
-void Scheduler::RescheduleBeginImplFrameDeadlineIfNeeded() {
+void Scheduler::ScheduleBeginImplFrameDeadlineIfNeeded() {
   if (settings_.using_synchronous_renderer_compositor)
     return;
 
@@ -628,9 +631,12 @@ void Scheduler::RescheduleBeginImplFrameDeadlineIfNeeded() {
       SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_INSIDE_BEGIN_FRAME)
     return;
 
-  if (begin_impl_frame_deadline_mode_ !=
-      state_machine_.CurrentBeginImplFrameDeadlineMode())
-    ScheduleBeginImplFrameDeadline();
+  if (begin_impl_frame_deadline_mode_ ==
+          state_machine_.CurrentBeginImplFrameDeadlineMode() &&
+      BeginImplFrameDeadlinePending())
+    return;
+
+  ScheduleBeginImplFrameDeadline();
 }
 
 void Scheduler::OnBeginImplFrameDeadline() {
@@ -650,20 +656,9 @@ void Scheduler::OnBeginImplFrameDeadline() {
           "461509 Scheduler::OnBeginImplFrameDeadline1"));
   state_machine_.OnBeginImplFrameDeadline();
   ProcessScheduledActions();
-  state_machine_.OnBeginImplFrameIdle();
-  ProcessScheduledActions();
-
-  client_->DidBeginImplFrameDeadline();
-  frame_source_->DidFinishFrame(begin_retro_frame_args_.size());
+  FinishImplFrame();
 }
 
-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");
@@ -748,6 +743,10 @@ void Scheduler::ProcessScheduledActions() {
       case SchedulerStateMachine::ACTION_PREPARE_TILES:
         client_->ScheduledActionPrepareTiles();
         break;
+      case SchedulerStateMachine::ACTION_INVALIDATE_OUTPUT_SURFACE: {
+        client_->ScheduledActionInvalidateOutputSurface();
+        break;
+      }
     }
   } while (action != SchedulerStateMachine::ACTION_NONE);
 
@@ -755,7 +754,7 @@ void Scheduler::ProcessScheduledActions() {
 
   client_->DidAnticipatedDrawTimeChange(AnticipatedDrawTime());
 
-  RescheduleBeginImplFrameDeadlineIfNeeded();
+  ScheduleBeginImplFrameDeadlineIfNeeded();
 
   SetupNextBeginFrameIfNeeded();
 }
@@ -796,8 +795,6 @@ void Scheduler::AsValueInto(base::trace_event::TracedValue* state) const {
                     !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");