cc: Cleanup DelayBasedTimeSource code.

cc/scheduler/begin_frame_source.cc

 // Copyright 2014 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/begin_frame_source.h"
 
 #include "base/auto_reset.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 203 matching lines @@
 }
 
 SyntheticBeginFrameSource::SyntheticBeginFrameSource(
     scoped_ptr<DelayBasedTimeSource> time_source)
     : BeginFrameSourceBase(), time_source_(time_source.Pass()) {
   time_source_->SetActive(false);
   time_source_->SetClient(this);
 }
 
 SyntheticBeginFrameSource::~SyntheticBeginFrameSource() {
-  if (NeedsBeginFrames())
-    time_source_->SetActive(false);
+  time_source_->SetActive(false);
 }
 
 void SyntheticBeginFrameSource::OnUpdateVSyncParameters(
     base::TimeTicks new_vsync_timebase,
     base::TimeDelta new_vsync_interval) {
   time_source_->SetTimebaseAndInterval(new_vsync_timebase, new_vsync_interval);
 }
 
 BeginFrameArgs SyntheticBeginFrameSource::CreateBeginFrameArgs(
     base::TimeTicks frame_time,
     BeginFrameArgs::BeginFrameArgsType type) {
   base::TimeTicks deadline = time_source_->NextTickTime();
   return BeginFrameArgs::Create(BEGINFRAME_FROM_HERE, frame_time, deadline,
                                 time_source_->Interval(), type);
 }
 
-// TimeSourceClient support
+// DelayBasedTimeSourceClient support
 void SyntheticBeginFrameSource::OnTimerTick() {
   CallOnBeginFrame(CreateBeginFrameArgs(time_source_->LastTickTime(),
                                         BeginFrameArgs::NORMAL));
 }
 
 // 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()) {
+    DCHECK(needs_begin_frames);
     CallOnBeginFrame(
         CreateBeginFrameArgs(missed_tick_time, BeginFrameArgs::MISSED));
   }
 }
 
 // Tracing support
 void SyntheticBeginFrameSource::AsValueInto(
     base::trace_event::TracedValue* dict) const {
   dict->SetString("type", "SyntheticBeginFrameSource");
   BeginFrameSourceBase::AsValueInto(dict);
@@ skipping 196 matching lines @@
   if (!observer_->LastUsedBeginFrameArgs().IsValid())
     return true;
 
   // Only allow new args have a *strictly bigger* frame_time value and statisfy
   // minimum interval requirement.
   return (args.frame_time >=
           observer_->LastUsedBeginFrameArgs().frame_time + minimum_interval_);
 }
 
 }  // namespace cc