Adding the ability to use a simulated clock for unit tests.

webrtc/base/timing.h

 /*
  *  Copyright 2008 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_BASE_TIMING_H_
 #define WEBRTC_BASE_TIMING_H_
 
 namespace rtc {
 
+// TODO(deadbeef): Remove this and use ClockInterface instead.
 class Timing {
  public:
   Timing();
   virtual ~Timing();
 
   // WallTimeNow() returns the current wall-clock time in seconds,
   // within 10 milliseconds resolution.
   // WallTimeNow is static and does not require a timer_handle_ on Windows.
   static double WallTimeNow();
 
   // TimerNow() is like WallTimeNow(), but is monotonically
   // increasing.  It returns seconds in resolution of 10 microseconds
   // or better.  Although timer and wall-clock time have the same
   // timing unit, they do not necessarily correlate because wall-clock
   // time may be adjusted backwards, hence not monotonic.
   // Made virtual so we can make a fake one.
   // TODO(tommi): The only place we use this (virtual) is in
   // rtpdata_engine_unittest.cc.  See if it doesn't make more sense to change
   // that contract or test than to modify this generic class.
   virtual double TimerNow();
 };
 
 }  // namespace rtc
 
 #endif // WEBRTC_BASE_TIMING_H_