[Video] Add dummy video/audio tracks inactive to select them later.

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 266 matching lines @@
     case WebMediaPlayer::PreloadMetaData:
       return "metadata";
     case WebMediaPlayer::PreloadAuto:
       return "auto";
   }
 
   NOTREACHED();
   return String();
 }
 
+bool hasAudioVideoTracks() {

[chcunningham, 2016/11/29 22:39:18]

You can make this a media:: namespaced utilitiy method. See
https://cs.chromium.org/chromium/src/media/base/media.h

[mlamouri (slow - plz ping), 2016/11/30 09:34:00]

That wouldn't be available from Blink. Or did you mean creating something
similar in Blink?

[whywhat, 2016/11/30 20:45:39]

I've put it into HTMLMediaElement as a public static method. Both MediaSource
and SourceBuffer already use HTMLMediaElement and depend on it supporting media
tracks so seems fair.

+  return RuntimeEnabledFeatures::audioVideoTracksEnabled() ||
+         RuntimeEnabledFeatures::backgroundVideoTrackOptimizationEnabled();
+}

[mlamouri (slow - plz ping), 2016/11/30 09:34:00]

nit: can you name the method hasAudioVideoTracksEnabled()? I think the name
might be very confusing otherwise.

[whywhat, 2016/11/30 20:45:39]

The meaning is not about the feature enabled but if the media element uses media
tracks for the default source (if the page is not using the tracks itself).

mediaTracksEnabledInternally it is :)

+
 }  // anonymous namespace
 
 class HTMLMediaElement::AutoplayHelperClientImpl
     : public AutoplayExperimentHelper::Client {
  public:
   static AutoplayHelperClientImpl* create(HTMLMediaElement* element) {
     return new AutoplayHelperClientImpl(element);
   }
 
   virtual ~AutoplayHelperClientImpl();
@@ skipping 2261 matching lines @@
 }
 
 AudioTrackList& HTMLMediaElement::audioTracks() {
   return *m_audioTracks;
 }
 
 void HTMLMediaElement::audioTrackChanged(AudioTrack* track) {
   BLINK_MEDIA_LOG << "audioTrackChanged(" << (void*)this
                   << ") trackId= " << String(track->id())
                   << " enabled=" << boolString(track->enabled());
-  DCHECK(RuntimeEnabledFeatures::audioVideoTracksEnabled());
+  DCHECK(hasAudioVideoTracks());
 
   audioTracks().scheduleChangeEvent();
 
   if (m_mediaSource)
     m_mediaSource->onTrackChanged(track);
 
   if (!m_audioTracksTimer.isActive())
     m_audioTracksTimer.startOneShot(0, BLINK_FROM_HERE);
 }
 
@@ skipping 34 matching lines @@
 }
 
 VideoTrackList& HTMLMediaElement::videoTracks() {
   return *m_videoTracks;
 }
 
 void HTMLMediaElement::selectedVideoTrackChanged(VideoTrack* track) {
   BLINK_MEDIA_LOG << "selectedVideoTrackChanged(" << (void*)this
                   << ") selectedTrackId="
                   << (track->selected() ? String(track->id()) : "none");
-  DCHECK(RuntimeEnabledFeatures::audioVideoTracksEnabled());
+  DCHECK(hasAudioVideoTracks());
 
   if (track->selected())
     videoTracks().trackSelected(track->id());
 
   videoTracks().scheduleChangeEvent();
 
   if (m_mediaSource)
     m_mediaSource->onTrackChanged(track);
 
   WebMediaPlayer::TrackId id = track->id();
@@ skipping 1219 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(HTMLMediaElement) {
   visitor->traceWrappers(m_videoTracks);
   visitor->traceWrappers(m_audioTracks);
   visitor->traceWrappers(m_textTracks);
   HTMLElement::traceWrappers(visitor);
 }
 
 void HTMLMediaElement::createPlaceholderTracksIfNecessary() {
-  if (!RuntimeEnabledFeatures::audioVideoTracksEnabled() &&
-      !RuntimeEnabledFeatures::backgroundVideoTrackOptimizationEnabled()) {
+  if (!hasAudioVideoTracks())
     return;
-  }
 
   // Create a placeholder audio track if the player says it has audio but it
   // didn't explicitly announce the tracks.
-  if (hasAudio() && !audioTracks().length())
+  if (hasAudio() && !audioTracks().length()) {
     addAudioTrack("audio", WebMediaPlayerClient::AudioTrackKindMain,
-                  "Audio Track", "", true);
+                  "Audio Track", "", false);
+  }
 
   // Create a placeholder video track if the player says it has video but it
   // didn't explicitly announce the tracks.
-  if (hasVideo() && !videoTracks().length())
+  if (hasVideo() && !videoTracks().length()) {
     addVideoTrack("video", WebMediaPlayerClient::VideoTrackKindMain,
-                  "Video Track", "", true);
+                  "Video Track", "", false);
+  }
 }
 
 void HTMLMediaElement::selectInitialTracksIfNecessary() {
-  if (!RuntimeEnabledFeatures::audioVideoTracksEnabled() &&
-      !RuntimeEnabledFeatures::backgroundVideoTrackOptimizationEnabled()) {
+  if (!hasAudioVideoTracks())
     return;
-  }
 
   // Enable the first audio track if an audio track hasn't been enabled yet.
   if (audioTracks().length() > 0 && !audioTracks().hasEnabledTrack())
     audioTracks().anonymousIndexedGetter(0)->setEnabled(true);
 
   // Select the first video track if a video track hasn't been selected yet.
   if (videoTracks().length() > 0 && videoTracks().selectedIndex() == -1)
     videoTracks().anonymousIndexedGetter(0)->setSelected(true);
 }
 
@@ skipping 306 matching lines @@
 
 IntRect HTMLMediaElement::AutoplayHelperClientImpl::absoluteBoundingBoxRect()
     const {
   IntRect result;
   if (LayoutObject* object = m_element->layoutObject())
     result = object->absoluteBoundingBoxRect();
   return result;
 }
 
 }  // namespace blink