Change base::TickClock to a ref counted class.

ash/wm/maximize_mode/maximize_mode_controller.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 "ash/wm/maximize_mode/maximize_mode_controller.h"
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/accelerators/accelerator_table.h"
 #include "ash/accelerometer/accelerometer_controller.h"
 #include "ash/ash_switches.h"
@@ skipping 473 matching lines @@
   if (last_lid_open_time_.is_null())
     return false;
 
   base::TimeTicks now = tick_clock_->NowTicks();
   DCHECK(now >= last_lid_open_time_);
   base::TimeDelta elapsed_time = now - last_lid_open_time_;
   return elapsed_time <= kLidRecentlyOpenedDuration;
 }
 
 void MaximizeModeController::SetTickClockForTest(
-    scoped_ptr<base::TickClock> tick_clock) {
-  DCHECK(tick_clock_);
-  tick_clock_ = tick_clock.Pass();
+    const scoped_refptr<base::TickClock>& tick_clock) {
+  DCHECK(tick_clock_.get() != NULL);
+  tick_clock_ = tick_clock;
 }
 
 }  // namespace ash