Change base::TickClock to a ref counted class.

media/cast/test/skewed_tick_clock.h

 // 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.
 
 #ifndef CAST_MEDIA_TEST_SKEWED_TICK_CLOCK_H
 #define CAST_MEDIA_TEST_SKEWED_TICK_CLOCK_H
 
 #include "base/time/tick_clock.h"
 #include "base/time/time.h"
 
@@ skipping 10 matching lines @@
   // |skew| > 1.0 means clock runs faster.
   // |offset| > 0 means clock returns times from the future.
   // Note, |offset| is cumulative.
   // Also note that changing the skew will never make the clock
   // jump forwards or backwards, only changing the offset will
   // do that.
   void SetSkew(double skew, base::TimeDelta offset);
   virtual base::TimeTicks NowTicks() override;
 
  private:
+  virtual ~SkewedTickClock() {}
+
   base::TimeTicks SkewTicks(base::TimeTicks now);
   base::TickClock* clock_;  // Not owned.
   double skew_;
   base::TimeTicks last_skew_set_time_;
   base::TimeTicks skew_clock_at_last_set_;
 
   DISALLOW_COPY_AND_ASSIGN(SkewedTickClock);
 };
 
 }  // namespace test
 }  // namespace cast
 }  // namespace media
 
 #endif  // CAST_MEDIA_TEST_SKEWED_TICK_CLOCK_H