[Android, Media] Don't unlock MediaStream elements; instead allow MS to autoplay without a gesture.

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

Index: third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
index ed596d00d9df66b3052914fec0e6c9c47b0352e2..af2469c15f6eb4ccbbf85bb5bbe3dce9fba86f62 100644
--- a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
@@ -441,6 +441,7 @@ HTMLMediaElement::HTMLMediaElement(const QualifiedName& tagName, Document& docum
     , m_remoteRoutesAvailable(false)
     , m_playingRemotely(false)
     , m_inOverlayFullscreenVideo(false)
+    , m_unlockedUserGestureForMediaStream(false)
     , m_audioTracks(AudioTrackList::create(*this))
     , m_videoTracks(VideoTrackList::create(*this))
     , m_textTracks(nullptr)
@@ -455,12 +456,7 @@ HTMLMediaElement::HTMLMediaElement(const QualifiedName& tagName, Document& docum
 
     DVLOG(MEDIA_LOG_LEVEL) << "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_autoplayHelper->isExperimentEnabled()) {
-        m_lockedPendingUserGesture = true;
-    }
+    m_lockedPendingUserGesture = needToLockPendingUserGesture(document);
 
     setHasCustomStyleCallbacks();
     addElementToDocumentMap(this, &document);
@@ -499,10 +495,8 @@ void HTMLMediaElement::didMoveToNewDocument(Document& 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())
-        || m_autoplayHelper->isExperimentEnabled();
-    bool newDocumentRequiresUserGesture = (document().settings() && document().settings()->mediaPlaybackRequiresUserGesture())
-        || m_autoplayHelper->isExperimentEnabled();
+    bool oldDocumentRequiresUserGesture = needToLockPendingUserGesture(oldDocument);
+    bool newDocumentRequiresUserGesture = needToLockPendingUserGesture(document());
     if (newDocumentRequiresUserGesture && !oldDocumentRequiresUserGesture) {
         m_lockedPendingUserGesture = true;
     }
@@ -696,7 +690,12 @@ void HTMLMediaElement::setSrc(const AtomicString& url)
 void HTMLMediaElement::setSrcObject(MediaStreamDescriptor* srcObject)
 {
     DVLOG(MEDIA_LOG_LEVEL) << "setSrcObject(" << (void*)this << ")";
+
     m_srcObject = srcObject;
+
+    if (m_unlockedUserGestureForMediaStream)
+        lockUserGesture();
+
     invokeLoadAlgorithm();
 }
 
@@ -1011,6 +1010,9 @@ void HTMLMediaElement::loadResource(const WebMediaPlayerSource& source, ContentT
     // cache is an internal detail not exposed through the media element API.
     m_currentSrc = url;
 
+    if (m_unlockedUserGestureForMediaStream)
+        lockUserGesture();
+
     if (m_audioSourceNode)
         m_audioSourceNode->onCurrentSrcChanged(m_currentSrc);
 
@@ -1036,6 +1038,7 @@ void HTMLMediaElement::loadResource(const WebMediaPlayerSource& source, ContentT
         bool isMediaStream = source.isMediaStream() || (source.isURL() && isMediaStreamURL(url.getString()));
         if (isMediaStream) {
             m_autoplayHelper->unlockUserGesture(GesturelessPlaybackEnabledByStream);
+            m_unlockedUserGestureForMediaStream = true;
         } else {
             m_mediaSource = HTMLMediaSource::lookup(url.getString());
 
@@ -3699,6 +3702,19 @@ bool HTMLMediaElement::isLockedPendingUserGesture() const
 void HTMLMediaElement::unlockUserGesture()
 {
     m_lockedPendingUserGesture = false;
+    m_unlockedUserGestureForMediaStream = false;
+}
+
+void HTMLMediaElement::lockUserGesture()
+{
+    m_lockedPendingUserGesture = needToLockPendingUserGesture(document());
+    m_unlockedUserGestureForMediaStream = false;
+}
+
+bool HTMLMediaElement::needToLockPendingUserGesture(const Document& document) const
+{
+    return (document.settings() && document.settings()->mediaPlaybackRequiresUserGesture())
+        || m_autoplayHelper->isExperimentEnabled();
 }
 
 bool HTMLMediaElement::isGestureNeededForPlayback() const