Simplify ElementVisibilityObserver implementation.

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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1621 matching lines @@
 
             // If the autoplay experiment says that it's okay to play now,
             // then don't require a user gesture.
             m_autoplayHelper->becameReadyToPlay();
 
             if (!isGestureNeededForPlayback()) {
                 if (isHTMLVideoElement() && muted() && RuntimeEnabledFeatures::autoplayMutedVideosEnabled()) {
                     // We might end up in a situation where the previous
                     // observer didn't had time to fire yet. We can avoid
                     // creating a new one in this case.
-                    if (!m_autoplayVisibilityObserver) {
-                        m_autoplayVisibilityObserver = new ElementVisibilityObserver(this, WTF::bind(&HTMLMediaElement::onVisibilityChangedForAutoplay, wrapWeakPersistent(this)));
-                        m_autoplayVisibilityObserver->start();
-                    }
+                    if (!m_autoplayVisibilityObserver)
+                        m_autoplayVisibilityObserver = ElementVisibilityObserver::create(this, this);
                 } else {
                     m_paused = false;
                     invalidateCachedTime();
                     scheduleEvent(EventTypeNames::play);
                     scheduleNotifyPlaying();
                     m_autoplaying = false;
                 }
             }
         }
 
@@ skipping 2008 matching lines @@
     visitor->trace(m_textTracksWhenResourceSelectionBegan);
     visitor->trace(m_playPromiseResolvers);
     visitor->trace(m_playPromiseResolveList);
     visitor->trace(m_playPromiseRejectList);
     visitor->trace(m_audioSourceProvider);
     visitor->trace(m_autoplayHelperClient);
     visitor->trace(m_autoplayHelper);
     visitor->trace(m_srcObject);
     visitor->trace(m_autoplayVisibilityObserver);
     visitor->template registerWeakMembers<HTMLMediaElement, &HTMLMediaElement::clearWeakMembers>(this);
+    HTMLElement::trace(visitor);
     Supplementable<HTMLMediaElement>::trace(visitor);
-    HTMLElement::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 DEFINE_TRACE_WRAPPERS(HTMLMediaElement)
 {
     visitor->traceWrappers(m_videoTracks);
     visitor->traceWrappers(m_audioTracks);
     visitor->traceWrappers(m_textTracks);
     HTMLElement::traceWrappers(visitor);
 }
@@ skipping 217 matching lines @@
     }
 }
 
 void HTMLMediaElement::recordAutoplayUnmuteStatus(AutoplayUnmuteActionStatus status)
 {
     DEFINE_STATIC_LOCAL(EnumerationHistogram, autoplayUnmuteHistogram, ("Media.Video.Autoplay.Muted.UnmuteAction", AutoplayUnmuteActionMax));
 
     autoplayUnmuteHistogram.count(status);
 }
 
-void HTMLMediaElement::onVisibilityChangedForAutoplay(bool isVisible)
+void HTMLMediaElement::onVisibilityChanged(bool isVisible)
 {
     if (!isVisible)
         return;
 
     if (shouldAutoplay()) {
         m_paused = false;
         invalidateCachedTime();
         scheduleEvent(EventTypeNames::play);
         scheduleNotifyPlaying();
         m_autoplaying = false;
@@ skipping 114 matching lines @@
 
 IntRect HTMLMediaElement::AutoplayHelperClientImpl::absoluteBoundingBoxRect() const
 {
     IntRect result;
     if (LayoutObject* object = m_element->layoutObject())
         result = object->absoluteBoundingBoxRect();
     return result;
 }
 
 } // namespace blink