Revert r95841 due to failing media_unittests on linux_shared bot.

media/base/clock.h

 // Copyright (c) 2011 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 MEDIA_BASE_CLOCK_H_
 #define MEDIA_BASE_CLOCK_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
-#include "media/base/media_export.h"
 
 namespace media {
 
 // A clock represents a single source of time to allow audio and video streams
 // to synchronize with each other.  Clock essentially tracks the media time with
 // respect to some other source of time, whether that may be the system clock or
 // updates via SetTime(). Clock uses linear interpolation to calculate the
 // current media time since the last time SetTime() was called.
 //
 // Clocks start off paused with a playback rate of 1.0f and a media time of 0.
 //
 // Clock is not thread-safe and must be externally locked.
 //
 // TODO(scherkus): Clock will some day be responsible for executing callbacks
 // given a media time.  This will be used primarily by video renderers.  For now
 // we'll keep using a poll-and-sleep solution.
-class MEDIA_EXPORT Clock {
+class Clock {
  public:
   // Type for a static function pointer that acts as a time source.
   typedef base::Time(TimeProvider)();
 
   Clock(TimeProvider* time_provider);
   ~Clock();
 
   // Starts the clock and returns the current media time, which will increase
   // with respect to the current playback rate.
   base::TimeDelta Play();
@@ skipping 36 matching lines @@
 
   // Current playback rate.
   float playback_rate_;
 
   DISALLOW_COPY_AND_ASSIGN(Clock);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_CLOCK_H_