Change base::TickClock to a ref counted class.

media/filters/video_frame_scheduler_impl.cc

Index: media/filters/video_frame_scheduler_impl.cc
diff --git a/media/filters/video_frame_scheduler_impl.cc b/media/filters/video_frame_scheduler_impl.cc
index ee06bb1cd96b7dbc70517ec061b2c1b572315f24..22551457f4925c0566b37172ac74a1274b3ea026 100644
--- a/media/filters/video_frame_scheduler_impl.cc
+++ b/media/filters/video_frame_scheduler_impl.cc
@@ -39,8 +39,8 @@ void VideoFrameSchedulerImpl::Reset() {
 }
 
 void VideoFrameSchedulerImpl::SetTickClockForTesting(
-    scoped_ptr<base::TickClock> tick_clock) {
-  tick_clock_.swap(tick_clock);
+    const scoped_refptr<base::TickClock>& tick_clock) {
+  tick_clock_ = tick_clock;
 }
 
 void VideoFrameSchedulerImpl::ResetTimerIfNecessary() {