Fix more warnings on linux

Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 1607 matching lines @@
         documentElementStyle = styleResolver()->styleForElement(documentElement());
 
     RefPtr<RenderStyle> bodyStyle = 0;
     if (body()) {
         bodyStyle = body()->renderStyle();
         if (!bodyStyle || body()->needsStyleRecalc() || documentElement()->needsStyleRecalc() || change == Force)
             bodyStyle = styleResolver()->styleForElement(body(), documentElementStyle.get());
     }
 
     WritingMode rootWritingMode = documentElementStyle->writingMode();
-    bool isHorizontalWritingMode = documentElementStyle->isHorizontalWritingMode();
     TextDirection rootDirection = documentElementStyle->direction();
 
     if (!writingModeSetOnDocumentElement() && body()) {
         rootWritingMode = bodyStyle->writingMode();
-        isHorizontalWritingMode = bodyStyle->isHorizontalWritingMode();
     }
 
     if (!directionSetOnDocumentElement() && body())
         rootDirection = bodyStyle->direction();
 
     RefPtr<RenderStyle> documentStyle = renderView->style();
     if (documentStyle->writingMode() != rootWritingMode || documentStyle->direction() != rootDirection) {
         RefPtr<RenderStyle> newStyle = RenderStyle::clone(documentStyle.get());
         newStyle->setWritingMode(rootWritingMode);
         newStyle->setDirection(rootDirection);
@@ skipping 3696 matching lines @@
 void Document::modifiedStyleSheet(StyleSheet* sheet, RecalcStyleTime when, StyleResolverUpdateMode updateMode)
 {
     if (!isActive())
         return;
 
     styleEngine()->modifiedStyleSheet(sheet);
     styleResolverChanged(when, updateMode);
 }
 
 } // namespace WebCore