Adding an experimental flag to block autoplay with sound in cross-origin iframes

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 270 matching lines @@
     case WebMediaPlayer::PreloadMetaData:
       return "metadata";
     case WebMediaPlayer::PreloadAuto:
       return "auto";
   }
 
   NOTREACHED();
   return String();
 }
 
+bool isDocumentCrossOrigin(Document& document) {
+  const LocalFrame* frame = document.frame();
+  return frame && frame->isCrossOriginSubframe();
+}
+
+// Return true if and only if the document settings specifies media playback
+// requires user gesture.
+bool computeLockedPendingUserGesture(Document& document) {
+  if (!document.settings())
+    return false;
+
+  if (document.settings()->crossOriginMediaPlaybackRequiresUserGesture() &&
+      isDocumentCrossOrigin(document)) {
+    return true;
+  }
+
+  return document.settings()->mediaPlaybackRequiresUserGesture();
+}
+
 }  // anonymous namespace
 
 MIMETypeRegistry::SupportsType HTMLMediaElement::supportsType(
     const ContentType& contentType) {
   DEFINE_STATIC_LOCAL(const String, codecs, ("codecs"));
 
   String type = contentType.type().lower();
   // The codecs string is not lower-cased because MP4 values are case sensitive
   // per http://tools.ietf.org/html/rfc4281#page-7.
   String typeCodecs = contentType.parameter(codecs);
@@ skipping 94 matching lines @@
       m_videoTracks(this, VideoTrackList::create(*this)),
       m_textTracks(this, nullptr),
       m_audioSourceNode(nullptr),
       m_autoplayUmaHelper(AutoplayUmaHelper::create(this)),
       m_remotePlaybackClient(nullptr),
       m_autoplayVisibilityObserver(nullptr) {
   ThreadState::current()->registerPreFinalizer(this);
 
   BLINK_MEDIA_LOG << "HTMLMediaElement(" << (void*)this << ")";
 
-  // If any experiment is enabled, then we want to enable a user gesture by
-  // default, otherwise the experiment does nothing.
-  if ((document.settings() &&
-       document.settings()->mediaPlaybackRequiresUserGesture())) {
-    m_lockedPendingUserGesture = true;
-  }
+  m_lockedPendingUserGesture = computeLockedPendingUserGesture(document);
 
   LocalFrame* frame = document.frame();
   if (frame) {
     m_remotePlaybackClient =
         frame->loader().client()->createWebRemotePlaybackClient(*this);
   }
 
   setHasCustomStyleCallbacks();
   addElementToDocumentMap(this, &document);
 
@@ skipping 23 matching lines @@
   clearMediaPlayerAndAudioSourceProviderClientWithoutLocking();
 }
 
 void HTMLMediaElement::didMoveToNewDocument(Document& oldDocument) {
   BLINK_MEDIA_LOG << "didMoveToNewDocument(" << (void*)this << ")";
 
   m_autoplayUmaHelper->didMoveToNewDocument(oldDocument);
   // If any experiment is enabled, then we want to enable a user gesture by
   // default, otherwise the experiment does nothing.
   bool oldDocumentRequiresUserGesture =
-      (oldDocument.settings() &&
-       oldDocument.settings()->mediaPlaybackRequiresUserGesture());
+      computeLockedPendingUserGesture(oldDocument);
   bool newDocumentRequiresUserGesture =
-      (document().settings() &&
-       document().settings()->mediaPlaybackRequiresUserGesture());
+      computeLockedPendingUserGesture(document());
   if (newDocumentRequiresUserGesture && !oldDocumentRequiresUserGesture) {
     m_lockedPendingUserGesture = true;
   }
 
   if (m_shouldDelayLoadEvent) {
     document().incrementLoadEventDelayCount();
     // Note: Keeping the load event delay count increment on oldDocument that
     // was added when m_shouldDelayLoadEvent was set so that destruction of
     // m_webMediaPlayer can not cause load event dispatching in oldDocument.
   } else {
@@ skipping 3584 matching lines @@
       kMostlyFillViewportBecomeStableSeconds, BLINK_FROM_HERE);
 }
 
 void HTMLMediaElement::viewportFillDebouncerTimerFired(TimerBase*) {
   m_mostlyFillingViewport = true;
   if (m_webMediaPlayer)
     m_webMediaPlayer->becameDominantVisibleContent(m_mostlyFillingViewport);
 }
 
 }  // namespace blink