WIP (Introduce WTF::NonNullPtr<T>.)

Source/core/html/HTMLDocument.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 93 matching lines @@
         mode = on;
     else if (equalIgnoringCase(value, "off"))
         mode = off;
     else
         mode = inherit;
     Document::setDesignMode(mode);
 }
 
 Element* HTMLDocument::activeElement()
 {
-    if (Element* element = treeScope().adjustedFocusedElement())
+    if (Element* element = treeScope()->adjustedFocusedElement())
         return element;
     return body();
 }
 
 bool HTMLDocument::hasFocus()
 {
     Page* page = this->page();
     if (!page)
         return false;
     if (!page->focusController().isActive() || !page->focusController().isFocused())
@@ skipping 201 matching lines @@
 }
 
 void HTMLDocument::clear()
 {
     // FIXME: This does nothing, and that seems unlikely to be correct.
     // We've long had a comment saying that IE doesn't support this.
     // But I do see it in the documentation for Mozilla.
 }
 
 }