Change base::TickClock to a ref counted class.

content/renderer/media/render_media_log.h

Index: content/renderer/media/render_media_log.h
diff --git a/content/renderer/media/render_media_log.h b/content/renderer/media/render_media_log.h
index d17f543819db4b6bc931fdd6a5933308fe6cd2c7..4cb83395afb95d73d699cd4d581c783d915e10de 100644
--- a/content/renderer/media/render_media_log.h
+++ b/content/renderer/media/render_media_log.h
@@ -30,13 +30,13 @@ class CONTENT_EXPORT RenderMediaLog : public media::MediaLog {
   virtual void AddEvent(scoped_ptr<media::MediaLogEvent> event) override;
 
   // Will reset |last_ipc_send_time_| with the value of NowTicks().
-  void SetTickClockForTesting(scoped_ptr<base::TickClock> tick_clock);
+  void SetTickClockForTesting(const scoped_refptr<base::TickClock>& tick_clock);
 
  private:
   virtual ~RenderMediaLog();
 
   scoped_refptr<base::MessageLoopProxy> render_loop_;
-  scoped_ptr<base::TickClock> tick_clock_;
+  scoped_refptr<base::TickClock> tick_clock_;
   base::TimeTicks last_ipc_send_time_;
   std::vector<media::MediaLogEvent> queued_media_events_;