Merge WebKit r153448 (Optimizes the number of updateTextTrackDisplay calls)

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 1013 matching lines @@
         if (!currentCues.contains(previousCues[i]) && previousCues[i].data()->isActive())
             activeSetChanged = true;
 
     for (size_t i = 0; i < currentCuesSize; ++i) {
         currentCues[i].data()->updateDisplayTree(movieTime);
 
         if (!currentCues[i].data()->isActive())
             activeSetChanged = true;
     }
 
-    if (!activeSetChanged) {
-        // Even though the active set has not changed, it is possible that the
-        // the mode of a track has changed from 'hidden' to 'showing' and the
-        // cues have not yet been rendered.
-        // Note: don't call updateTextTrackDisplay() unless we have controls because it will
-        // create them.
-        if (hasMediaControls())

[acolwell GONE FROM CHROMIUM, 2013/08/12 20:19:02]

Why is this code dropped? Doesn't this result in a behavior change?

[vcarbune.chromium, 2013/08/19 22:20:12]

No, configureTextTrackDisplay now calls this if AssumeVisibleChange is passed. I
added a while ago this code and it's covered by
track-cue-rendering-mode-changed, which passes using the optimizations.

-            updateTextTrackDisplay();
+    if (!activeSetChanged)
         return;
-    }
 
     // 7 - If the time was reached through the usual monotonic increase of the
     // current playback position during normal playback, and there are cues in
     // other cues that have their text track cue pause-on-exi flag set and that
     // either have their text track cue active flag set or are also in missed
     // cues, then immediately pause the media element.
     for (size_t i = 0; !m_paused && i < previousCuesSize; ++i) {
         if (previousCues[i].data()->pauseOnExit()
             && previousCues[i].data()->isActive()
             && !currentCues.contains(previousCues[i]))
@@ skipping 180 matching lines @@
 
                 // If this is the first added track, create the list of text tracks.
                 if (!m_textTracks)
                   m_textTracks = TextTrackList::create(this, ActiveDOMObject::scriptExecutionContext());
             }
             break;
         }
     } else if (track->trackType() == TextTrack::AddTrack && track->mode() != TextTrack::disabledKeyword())
         textTrackAddCues(track, track->cues());
 
-    configureTextTrackDisplay();
-    updateActiveTextTrackCues(currentTime());
+    configureTextTrackDisplay(AssumeVisibleTextTracksChanged);
 }
 
 void HTMLMediaElement::textTrackKindChanged(TextTrack* track)
 {
     if (track->kind() != TextTrack::captionsKeyword() && track->kind() != TextTrack::subtitlesKeyword() && track->mode() == TextTrack::showingKeyword())
         track->setMode(TextTrack::hiddenKeyword());
 }
 
 void HTMLMediaElement::beginIgnoringTrackDisplayUpdateRequests()
 {
@@ skipping 2447 matching lines @@
             mediaControls()->hide();
         return;
     }
 
     if (!hasMediaControls() && !createMediaControls())
         return;
 
     mediaControls()->show();
 }
 
-void HTMLMediaElement::configureTextTrackDisplay()
+void HTMLMediaElement::configureTextTrackDisplay(ConfigureTextTrackDisplayFlags flags)
 {
     ASSERT(m_textTracks);
     LOG(Media, "HTMLMediaElement::configureTextTrackDisplay");
 
     if (m_processingPreferenceChange)
         return;
 
     bool haveVisibleTextTrack = false;
     for (unsigned i = 0; i < m_textTracks->length(); ++i) {
         if (m_textTracks->item(i)->mode() == TextTrack::showingKeyword()) {
             haveVisibleTextTrack = true;
             break;
         }
     }
 
-    if (m_haveVisibleTextTrack == haveVisibleTextTrack)
+    if (flags == DoNotAssumeVisibleTextTracksChanged
+        && m_haveVisibleTextTrack == haveVisibleTextTrack) {
+        updateActiveTextTrackCues(currentTime());
         return;
+    }
     m_haveVisibleTextTrack = haveVisibleTextTrack;
     m_closedCaptionsVisible = m_haveVisibleTextTrack;
 
     if (!m_haveVisibleTextTrack && !hasMediaControls())
         return;
     if (!hasMediaControls() && !createMediaControls())
         return;
 
     mediaControls()->changedClosedCaptionsVisibility();
 
@@ skipping 232 matching lines @@
 {
     m_restrictions = NoRestrictions;
 }
 
 void HTMLMediaElement::mediaPlayerScheduleLayerUpdate()
 {
     scheduleLayerUpdate();
 }
 
 }