Let MediaController.currentTime return the position previously set

Source/core/html/MediaController.cpp

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 152 matching lines @@
     // When the user agent is to seek the media controller to a particular new playback position,
     // it must follow these steps:
     // If the new playback position is less than zero, then set it to zero.
     time = max(0.0, time);
 
     // If the new playback position is greater than the media controller duration, then set it
     // to the media controller duration.
     time = min(time, duration());
 
     // Set the media controller position to the new playback position.
+    m_position = time;
     m_clock->setCurrentTime(time);
 
     // Seek each slaved media element to the new playback position relative to the media element timeline.
     for (size_t index = 0; index < m_mediaElements.size(); ++index)
         m_mediaElements[index]->seek(time, exceptionState);
 
     scheduleTimeupdateEvent();
 }
 
 void MediaController::unpause()
@@ skipping 430 matching lines @@
 {
     double now = WTF::currentTime();
     double timedelta = now - m_previousTimeupdateTime;
 
     if (timedelta < maxTimeupdateEventFrequency)
         return;
 
     scheduleEvent(EventTypeNames::timeupdate);
     m_previousTimeupdateTime = now;
 }