Use C++11 features in core/html

Source/core/html/track/TextTrack.cpp

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  * Copyright (C) 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 174 matching lines @@
 
 TextTrackCueList* TextTrack::cues()
 {
     // 4.8.10.12.5 If the text track mode ... is not the text track disabled mode,
     // then the cues attribute must return a live TextTrackCueList object ...
     // Otherwise, it must return null. When an object is returned, the
     // same object must be returned each time.
     // http://www.whatwg.org/specs/web-apps/current-work/#dom-texttrack-cues
     if (m_mode != disabledKeyword())
         return ensureTextTrackCueList();
-    return 0;
+    return nullptr;
 }
 
 void TextTrack::removeAllCues()
 {
     if (!m_cues)
         return;
 
     if (mediaElement())
         mediaElement()->textTrackRemoveCues(this, m_cues.get());
 
     for (size_t i = 0; i < m_cues->length(); ++i)
         m_cues->item(i)->setTrack(0);
 
     m_cues = nullptr;
 }
 
 TextTrackCueList* TextTrack::activeCues() const
 {
     // 4.8.10.12.5 If the text track mode ... is not the text track disabled mode,
     // then the activeCues attribute must return a live TextTrackCueList object ...
     // ... whose active flag was set when the script started, in text track cue
     // order. Otherwise, it must return null. When an object is returned, the
     // same object must be returned each time.
     // http://www.whatwg.org/specs/web-apps/current-work/#dom-texttrack-activecues
     if (m_cues && m_mode != disabledKeyword())
         return m_cues->activeCues();
-    return 0;
+    return nullptr;
 }
 
 void TextTrack::addCue(PassRefPtrWillBeRawPtr<TextTrackCue> prpCue)
 {
     if (!prpCue)
         return;
 
     RefPtrWillBeRawPtr<TextTrackCue> cue = prpCue;
 
     // TODO(93143): Add spec-compliant behavior for negative time values.
@@ skipping 56 matching lines @@
 VTTRegionList* TextTrack::regions()
 {
     // If the text track mode of the text track that the TextTrack object
     // represents is not the text track disabled mode, then the regions
     // attribute must return a live VTTRegionList object that represents
     // the text track list of regions of the text track. Otherwise, it must
     // return null. When an object is returned, the same object must be returned
     // each time.
     if (RuntimeEnabledFeatures::webVTTRegionsEnabled() && m_mode != disabledKeyword())
         return ensureVTTRegionList();
-    return 0;
+    return nullptr;
 }
 
 void TextTrack::addRegion(PassRefPtrWillBeRawPtr<VTTRegion> prpRegion)
 {
     if (!prpRegion)
         return;
 
     RefPtrWillBeRawPtr<VTTRegion> region = prpRegion;
     VTTRegionList* regionList = ensureVTTRegionList();
 
@@ skipping 130 matching lines @@
 void TextTrack::trace(Visitor* visitor)
 {
     visitor->trace(m_cues);
     visitor->trace(m_regions);
     visitor->trace(m_trackList);
     TrackBase::trace(visitor);
     EventTargetWithInlineData::trace(visitor);
 }
 
 } // namespace blink