cc: Cleanup DelayBasedTimeSource code.

cc/scheduler/begin_frame_source.cc

Index: cc/scheduler/begin_frame_source.cc
diff --git a/cc/scheduler/begin_frame_source.cc b/cc/scheduler/begin_frame_source.cc
index bc828026303bce098331606e8c675a73bf5ff110..e7f6425f4d24f5f8585cfc09eaf5441624127253 100644
--- a/cc/scheduler/begin_frame_source.cc
+++ b/cc/scheduler/begin_frame_source.cc
@@ -210,12 +210,17 @@ scoped_ptr<SyntheticBeginFrameSource> SyntheticBeginFrameSource::Create(
     base::TimeDelta initial_vsync_interval) {
   scoped_ptr<DelayBasedTimeSource> time_source =
       DelayBasedTimeSource::Create(initial_vsync_interval, task_runner);
-  return make_scoped_ptr(new SyntheticBeginFrameSource(time_source.Pass()));
+  return make_scoped_ptr(
+      new SyntheticBeginFrameSource(task_runner, time_source.Pass()));
 }
 
 SyntheticBeginFrameSource::SyntheticBeginFrameSource(
+    base::SingleThreadTaskRunner* task_runner,
     scoped_ptr<DelayBasedTimeSource> time_source)
-    : BeginFrameSourceBase(), time_source_(time_source.Pass()) {
+    : BeginFrameSourceBase(),
+      task_runner_(task_runner),
+      time_source_(time_source.Pass()),
+      weak_factory_(this) {
   time_source_->SetActive(false);
   time_source_->SetClient(this);
 }
@@ -239,7 +244,12 @@ BeginFrameArgs SyntheticBeginFrameSource::CreateBeginFrameArgs(
                                 time_source_->Interval(), type);
 }
 
-// TimeSourceClient support
+// DelayBasedTimeSourceClient support
+void SyntheticBeginFrameSource::OnMissedTick() {

[mithro-old, 2015/06/30 08:11:52]

I feel like these callbacks should just take a time value?

+  CallOnBeginFrame(CreateBeginFrameArgs(time_source_->MissedTickTime(),
+                                        BeginFrameArgs::MISSED));
+}
+
 void SyntheticBeginFrameSource::OnTimerTick() {
   CallOnBeginFrame(CreateBeginFrameArgs(time_source_->LastTickTime(),
                                         BeginFrameArgs::NORMAL));
@@ -248,12 +258,7 @@ void SyntheticBeginFrameSource::OnTimerTick() {
 // BeginFrameSourceBase support
 void SyntheticBeginFrameSource::OnNeedsBeginFramesChange(
     bool needs_begin_frames) {
-  base::TimeTicks missed_tick_time =
-      time_source_->SetActive(needs_begin_frames);
-  if (!missed_tick_time.is_null()) {
-    CallOnBeginFrame(
-        CreateBeginFrameArgs(missed_tick_time, BeginFrameArgs::MISSED));
-  }
+  time_source_->SetActive(needs_begin_frames);
 }
 
 // Tracing support