[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 bff62e7bfdb250473405fbd5bc2215a8d99b8bf2..0af541c17e923d2be94add6c7200fd8b2d37c148 100644
--- a/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLMediaElement.cpp
@@ -1034,9 +1034,7 @@ void HTMLMediaElement::loadResource(const WebMediaPlayerSource& source, const Co
     bool isStreamOrBlobUrl = source.isMediaStream() || url.protocolIs(mediaSourceBlobProtocol);
     if (isStreamOrBlobUrl) {

[sof, 2016/06/27 15:10:47]

The logic looks a bit strange now - more readable as

  if (isStreamOrBlobUrl && !source.isMediaStream()) 

perhaps?

[whywhat, 2016/06/27 15:35:58]

Ok, I guess the overall condition triggering the code below comes down to

((source.isMediaStream() || url.protocolIs(mediaSourceBlobProtocol) &&
!source.isMediaStream() && (!source.isURL() ||
!isMediaStreamURL(url.getString()))

We could definitely remove source.isMediaStrem() from the first bracket:

url.protocolIs(mediaSourceBlobProtocol) && !source.isMediaStream() &&
(!source.isURL() || !isMediaStreamURL(url.getString()))

Maybe replace with:

isMediaStream = source.isMediaStream() || (source.isURL() &&
isMediaStreamURL(url.getString()));
isMediaSourceUrl = url.protocolIs(mediaSourceBlobProtocol) && !isMediaStream;
if (isMediaSourceUrl) {
  m_mediaSource = ...
  ...
}

WDYT?

Hm, isStreamOrBlobUrl is used elsewhere :(

Seems like "source.isURL() && isMediaStreamURL(url.getString())" is important
for m_mediaSource logic nested below but not for isStreamOrBlobUrl below? Does
it mean registered media stream URLs are ignored sometimes?

[sof, 2016/06/27 18:54:06]

That makes it a lot clearer, i.e., check if a media source blob: URL is for a
registered source. And try to use that media source, if so.

I'd just leave the isStreamOrBlobUrl as it is.
That question I'll leave to the grownups working with media element every day :)

[whywhat, 2016/06/27 19:00:50]

Not sure if it became much more clearer but I took a stab at it. Further
suggestions are welcome.

         bool isMediaStream = source.isMediaStream() || (source.isURL() && isMediaStreamURL(url.getString()));
-        if (isMediaStream) {
-            m_autoplayHelper->unlockUserGesture(GesturelessPlaybackEnabledByStream);
-        } else {
+        if (!isMediaStream) {
             m_mediaSource = HTMLMediaSource::lookup(url.getString());
 
             if (m_mediaSource) {
@@ -1223,7 +1221,7 @@ WebMediaPlayer::LoadType HTMLMediaElement::loadType() const
     if (m_mediaSource)
         return WebMediaPlayer::LoadTypeMediaSource;
 
-    if (m_srcObject || isMediaStreamURL(m_currentSrc.getString()))
+    if (m_srcObject || (!m_currentSrc.isNull() && isMediaStreamURL(m_currentSrc.getString())))
         return WebMediaPlayer::LoadTypeMediaStream;
 
     return WebMediaPlayer::LoadTypeURL;
@@ -3725,6 +3723,9 @@ bool HTMLMediaElement::isGestureNeededForPlayback() const
     if (!m_lockedPendingUserGesture)
         return false;
 
+    if (loadType() == WebMediaPlayer::LoadTypeMediaStream)
+        return false;
+
     // We want to allow muted video to autoplay if:
     // - the flag is enabled;
     // - Data Saver is not enabled;