Revert of [Blink>Media] Fix a crash in autoplay caused by delayed visibility observation

third_party/WebKit/Source/core/html/HTMLMediaElement.cpp

 /*
  * Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013 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
@@ skipping 3987 matching lines @@
   }
 
   DEFINE_STATIC_LOCAL(EnumerationHistogram, histogram,
                       ("Media.Controls.Show.Audio", MediaControlsShowMax));
   return histogram;
 }
 
 void HTMLMediaElement::onVisibilityChangedForAutoplay(bool isVisible) {
   if (!isVisible)
     return;
-  // Visibility change might be notified after stopping the observer, as it is a
-  // delayed task. Abort the steps if this happens.
-  if (!m_autoplayVisibilityObserver)
-    return;
 
   if (shouldAutoplay()) {
     m_paused = false;
     scheduleEvent(EventTypeNames::play);
     scheduleNotifyPlaying();
     m_autoplaying = false;
 
     updatePlayState();
   }
 
@@ skipping 110 matching lines @@
       kMostlyFillViewportBecomeStableSeconds, BLINK_FROM_HERE);
 }
 
 void HTMLMediaElement::viewportFillDebouncerTimerFired(TimerBase*) {
   m_mostlyFillingViewport = true;
   if (m_webMediaPlayer)
     m_webMediaPlayer->becameDominantVisibleContent(m_mostlyFillingViewport);
 }
 
 }  // namespace blink