Remove useless null checks from Node::document() call sites

Source/core/html/HTMLElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Motorola Mobility. 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
@@ skipping 911 matching lines @@
 {
     Node* strongDirectionalityTextNode;
     TextDirection textDirection = directionality(&strongDirectionalityTextNode);
     setHasDirAutoFlagRecursively(this, true, strongDirectionalityTextNode);
     if (renderer() && renderer()->style() && renderer()->style()->direction() != textDirection)
         setNeedsStyleRecalc();
 }
 
 void HTMLElement::adjustDirectionalityIfNeededAfterChildrenChanged(Node* beforeChange, int childCountDelta)
 {
-    if ((!document() || document()->renderer()) && childCountDelta < 0) {
+    if (document()->renderer() && childCountDelta < 0) {
         Node* node = beforeChange ? NodeTraversal::nextSkippingChildren(beforeChange) : 0;
         for (int counter = 0; node && counter < childCountDelta; counter++, node = NodeTraversal::nextSkippingChildren(node)) {
             if (elementAffectsDirectionality(node))
                 continue;
 
             setHasDirAutoFlagRecursively(node, false);
         }
     }
 
     if (!selfOrAncestorHasDirAutoAttribute())
@@ skipping 156 matching lines @@
 #ifndef NDEBUG
 
 // For use in the debugger
 void dumpInnerHTML(WebCore::HTMLElement*);
 
 void dumpInnerHTML(WebCore::HTMLElement* element)
 {
     printf("%s\n", element->innerHTML().ascii().data());
 }
 #endif