Allow muted third-party autoplay with -ormuted experiment option.

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 285 matching lines @@
 
     using RecordMetricsBehavior = HTMLMediaElement::RecordMetricsBehavior;
 
     double currentTime() const override { return m_element->currentTime(); }
     double duration() const override { return m_element->duration(); }
     bool paused() const override { return m_element->paused(); }
     bool ended() const override { return m_element->ended(); }
     bool muted() const override { return m_element->muted(); }
     void setMuted(bool muted) override { m_element->setMuted(muted); }
     void playInternal() override { m_element->playInternal(); }
+    void pauseInternal() override { m_element->pauseInternal(); }
     bool isLockedPendingUserGesture() const override { return m_element->isLockedPendingUserGesture(); }
     void unlockUserGesture() override { m_element->unlockUserGesture(); }
     void recordAutoplayMetric(AutoplayMetrics metric) override { m_element->recordAutoplayMetric(metric); }
     bool shouldAutoplay() override
     {
         return m_element->shouldAutoplay(RecordMetricsBehavior::DoNotRecord);
     }
     bool isHTMLVideoElement() const override { return m_element->isHTMLVideoElement(); }
     bool isHTMLAudioElement() const override { return m_element->isHTMLAudioElement(); }
 
@@ skipping 1929 matching lines @@
 }
 
 void HTMLMediaElement::setMuted(bool muted)
 {
     WTF_LOG(Media, "HTMLMediaElement::setMuted(%p, %s)", this, boolString(muted));
 
     if (m_muted == muted)
         return;
 
     m_muted = muted;
+    m_autoplayHelper->mutedChanged();
 
     updateVolume();
 
     if (muted)
         Platform::current()->recordAction(UserMetricsAction("Media_Playback_Mute_On"));
     else
         Platform::current()->recordAction(UserMetricsAction("Media_Playback_Mute_Off"));
 
     scheduleEvent(EventTypeNames::volumechange);
 }
@@ skipping 1618 matching lines @@
 
 IntRect HTMLMediaElement::AutoplayHelperClientImpl::absoluteBoundingBoxRect() const
 {
     IntRect result;
     if (LayoutObject* object = m_element->layoutObject())
         result = object->absoluteBoundingBoxRect();
     return result;
 }
 
 } // namespace blink