cc: Remove background ticking from LTHI.

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index 37e7c5352b0db92479aa8e49e6c04431cca1a8a7..2f1a42ae61bb5ec8987d461f2ee6b4d48bf61ceb 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -49,21 +49,6 @@ BeginFrameSource* SchedulerFrameSourcesConstructor::ConstructPrimaryFrameSource(
 }
 
 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",
@@ -83,13 +68,11 @@ Scheduler::Scheduler(
     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),
       authoritative_vsync_interval_(base::TimeDelta()),
       last_vsync_timebase_(base::TimeTicks()),
-      throttle_frame_production_(scheduler_settings.throttle_frame_production),
+      throttle_frame_production_(false),
       settings_(scheduler_settings),
       client_(client),
       layer_tree_host_id_(layer_tree_host_id),
@@ -123,15 +106,12 @@ Scheduler::Scheduler(
   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_);
+
+  SetThrottleFrameProduction(scheduler_settings.throttle_frame_production);
 }
 
 Scheduler::~Scheduler() {
@@ -174,21 +154,11 @@ void Scheduler::SetCanStart() {
 }
 
 void Scheduler::UpdateActiveFrameSource() {

[brianderson, 2015/04/01 21:58:08]

Delete?

[mithro-old, 2015/04/02 01:03:59]

Done.

-  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_);

[jdduke (slow), 2015/04/01 19:21:21]

Why not set the active source to null if we're invisible? Or does that mess with
scheduling? I guess as long as we're not ticking or posting tasks at all when
we're invisible (regardless of the active source), that's enough.

[mithro-old, 2015/04/02 01:03:59]

The approach I took was to make scheduler understand that SetNeedsBeginFrame is
dependent on visibility. I feel this is a cleaner approach because the scheduler
has a better understanding of what is going on then.

-  }
-  ProcessScheduledActions();
 }
 
 void Scheduler::SetVisible(bool visible) {
   state_machine_.SetVisible(visible);
-  UpdateActiveFrameSource();
+  ProcessScheduledActions();
 }
 
 void Scheduler::SetCanDraw(bool can_draw) {
@@ -208,7 +178,12 @@ void Scheduler::NotifyReadyToDraw() {
 
 void Scheduler::SetThrottleFrameProduction(bool throttle) {
   throttle_frame_production_ = throttle;
-  UpdateActiveFrameSource();
+  if (throttle) {
+    frame_source_->SetActiveSource(primary_frame_source_);
+  } else {
+    frame_source_->SetActiveSource(unthrottled_frame_source_);
+  }
+  ProcessScheduledActions();
 }
 
 void Scheduler::SetNeedsCommit() {