When HLS redirects are encountered recreate WebMediaPlayer.

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 898 matching lines @@
         DVLOG(MEDIA_LOG_LEVEL) << "selectMediaResource(" << (void*)this << "), nothing to load";
         return;
     }
 
     // 7 - Set the media element's networkState to NETWORK_LOADING.
     setNetworkState(NETWORK_LOADING);
 
     // 8 - Queue a task to fire a simple event named loadstart at the media element.
     scheduleEvent(EventTypeNames::loadstart);
 
+    // Reload a post-redirect URL from a previous WebMediaPlayer instance. This provides a
+    // workaround for WebMediaPlayer instances which discover they can't play a URL after
+    // redirects have been followed.
+    // TODO(tguilbert): Remove once http://crbug.com/580626 is fixed.
+    if (webMediaPlayer()) {
+        WebURL alternativeSourceURL = webMediaPlayer()->alternativeSourceURL();
+        if (!alternativeSourceURL.isEmpty()) {
+            resetMediaPlayerAndMediaSource();
+            ContentType contentType((String()));
+            loadResource(WebMediaPlayerSource(alternativeSourceURL), contentType);
+            return;
+        }
+    }
+
     // 9 - Run the appropriate steps...
     switch (mode) {
     case Object:
         loadSourceFromObject();
         DVLOG(MEDIA_LOG_LEVEL) << "selectMediaResource(" << (void*)this << ", using 'srcObject' attribute";
         break;
     case Attribute:
         loadSourceFromAttribute();
         DVLOG(MEDIA_LOG_LEVEL) << "selectMediaResource(" << (void*)this << "), using 'src' attribute url";
         break;
@@ skipping 492 matching lines @@
 
 void HTMLMediaElement::networkStateChanged()
 {
     setNetworkState(webMediaPlayer()->getNetworkState());
 }
 
 void HTMLMediaElement::mediaLoadingFailed(WebMediaPlayer::NetworkState error)
 {
     stopPeriodicTimers();
 
+    // WebMediaPlayer encountered a resource it can't play, retry the loading with a new WebMediaPlayer instance using the post-redirect URL.
+    // TODO(tguilbert): Remove once http://crbug.com/580626 is fixed.

[foolip, 2016/06/20 10:30:44]

Will support for HLS be added to WMPI, or what's the path for full unification?

[DaleCurtis, 2016/06/20 18:54:25]

We'll be adding support for HLS to WMPI, but it will be accomplished by hosting
an Android MediaPlayer in an out-of-process Mojo shell. Here are some more
details on that flow:

https://docs.google.com/document/d/1DHdFhWPGe1holzQM1Leq5tmFI81s-FQ4wbx1CN8sD...

+    if (m_readyState < HAVE_METADATA && error == WebMediaPlayer::NetworkStateFormatError && webMediaPlayer() && !webMediaPlayer()->alternativeSourceURL().isEmpty()) {
+        scheduleNextSourceChild();

[foolip, 2016/06/20 10:30:44]

This will end up calling either loadNextSourceChild() or loadInternal(). For
loadNextSourceChild(), it looks like this won't work, the
resetMediaPlayerAndMediaSource() will ruin it all.

In the loadInternal() case, loadResource() will still run some steps twice that
seem problematic, like  setting m_currentSrc (exposing the redirected URL) and
updating m_muted. That can probably be observed by web content but shouldn't be.

Would a more surgical replacement of the m_webMediaPlayer do the trick, or are
there things that then end up out of sync? I'm thinking maybe a
WebMediaPlayerClient::requestReload(WebURL) that would (in a posted task)
destroy the old WebMediaPlayer and replace it with a new one while changing as
little state as possible. Maybe the end of HTMLMediaElement::startPlayerLoad
could be factored out.

[DaleCurtis, 2016/06/20 18:54:25]

This is a good idea. I don't think we need to post the task as far as I can
tell. We just need to be careful about making sure this is the last line of the
function when called. Otherwise I've implemented your suggestion and it work
well.

+        return;
+    }
+
     // If we failed while trying to load a <source> element, the movie was never parsed, and there are more
     // <source> children, schedule the next one
     if (m_readyState < HAVE_METADATA && m_loadState == LoadingFromSourceElement) {
 
         // resource selection algorithm
         // Step 9.Otherwise.9 - Failed with elements: Queue a task, using the DOM manipulation task source, to fire a simple event named error at the candidate element.
         if (m_currentSourceNode)
             m_currentSourceNode->scheduleErrorEvent();
         else
             DVLOG(MEDIA_LOG_LEVEL) << "setNetworkState(" << (void*)this << ") - error event not sent, <source> was removed";
@@ skipping 2543 matching lines @@
 
 IntRect HTMLMediaElement::AutoplayHelperClientImpl::absoluteBoundingBoxRect() const
 {
     IntRect result;
     if (LayoutObject* object = m_element->layoutObject())
         result = object->absoluteBoundingBoxRect();
     return result;
 }
 
 } // namespace blink