Rename ContextDestructionObserver to ContextLifecycleObserver

Source/core/html/track/TextTrackRegion.cpp

 /*
  * Copyright (C) 2013 Google 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 52 matching lines @@
 // The region doesn't have scrolling text, by default.
 static const bool defaultScroll = false;
 
 // Default region line-height (vh units)
 static const float lineHeight = 5.33;
 
 // Default scrolling animation time period (s).
 static const float scrollTime = 0.433;
 
 TextTrackRegion::TextTrackRegion(ScriptExecutionContext* context)
-    : ContextDestructionObserver(context)
+    : ContextLifecycleObserver(context)
     , m_id(emptyString())
     , m_width(defaultWidth)
     , m_heightInLines(defaultHeightInLines)
     , m_regionAnchor(FloatPoint(defaultAnchorPointX, defaultAnchorPointY))
     , m_viewportAnchor(FloatPoint(defaultAnchorPointX, defaultAnchorPointY))
     , m_scroll(defaultScroll)
     , m_regionDisplayTree(0)
     , m_cueContainer(0)
     , m_track(0)
     , m_currentTop(0)
@@ skipping 413 matching lines @@
 {
     LOG(Media, "TextTrackRegion::scrollTimerFired");
 
     stopTimer();
     displayLastTextTrackCueBox();
 }
 
 } // namespace WebCore
 
 #endif