Change base::TickClock to a ref counted class.

components/network_time/network_time_tracker.h

Index: components/network_time/network_time_tracker.h
diff --git a/components/network_time/network_time_tracker.h b/components/network_time/network_time_tracker.h
index 80fd0c22d537580f94e5a8554afdd2bd698cfc76..7b47bd80e6c39fc5da16c11cc9618ee4cbdcb177 100644
--- a/components/network_time/network_time_tracker.h
+++ b/components/network_time/network_time_tracker.h
@@ -5,7 +5,7 @@
 #ifndef COMPONENTS_NETWORK_TIME_NETWORK_TIME_TRACKER_H_
 #define COMPONENTS_NETWORK_TIME_NETWORK_TIME_TRACKER_H_
 
-#include "base/memory/scoped_ptr.h"
+#include "base/memory/ref_counted.h"
 #include "base/threading/thread_checker.h"
 #include "base/time/time.h"
 
@@ -24,7 +24,7 @@ class NetworkTimeTracker {
  public:
   static void RegisterPrefs(PrefRegistrySimple* registry);
 
-  NetworkTimeTracker(scoped_ptr<base::TickClock> tick_clock,
+  NetworkTimeTracker(const scoped_refptr<base::TickClock>& tick_clock,
                      PrefService* pref_service);
   ~NetworkTimeTracker();
 
@@ -50,7 +50,7 @@ class NetworkTimeTracker {
 
  private:
   // For querying current time ticks.
-  scoped_ptr<base::TickClock> tick_clock_;
+  scoped_refptr<base::TickClock> tick_clock_;
 
   PrefService* pref_service_;