Translate viewport related meta tags into @viewport descriptors as suggested by the CSS Device Adap…

Source/core/css/DocumentRuleSets.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 62 matching lines @@
 {
 }
 
 void DocumentRuleSets::initUserStyle(DocumentStyleSheetCollection* styleSheetCollection, const MediaQueryEvaluator& medium, StyleResolver& resolver)
 {
     OwnPtr<RuleSet> tempUserStyle = RuleSet::create();
     if (CSSStyleSheet* pageUserSheet = styleSheetCollection->pageUserSheet())
         tempUserStyle->addRulesFromSheet(pageUserSheet->contents(), medium, &resolver);
     collectRulesFromUserStyleSheets(styleSheetCollection->injectedUserStyleSheets(), *tempUserStyle, medium, resolver);
     collectRulesFromUserStyleSheets(styleSheetCollection->documentUserStyleSheets(), *tempUserStyle, medium, resolver);
-    if (tempUserStyle->ruleCount() > 0 || tempUserStyle->pageRules().size() > 0)
+    if (tempUserStyle->ruleCount() > 0 || tempUserStyle->pageRules().size() > 0 || tempUserStyle->viewportRules().size() > 0)
         m_userStyle = tempUserStyle.release();
 }
 
 void DocumentRuleSets::collectRulesFromUserStyleSheets(const Vector<RefPtr<CSSStyleSheet> >& userSheets, RuleSet& userStyle, const MediaQueryEvaluator& medium, StyleResolver& resolver)
 {
     for (unsigned i = 0; i < userSheets.size(); ++i) {
         ASSERT(userSheets[i]->contents()->isUserStyleSheet());
         userStyle.addRulesFromSheet(userSheets[i]->contents(), medium, &resolver);
     }
 }
@@ skipping 14 matching lines @@
     if (isViewSource)
         features.add(CSSDefaultStyleSheets::viewSourceStyle()->features());
 
     if (m_userStyle)
         features.add(m_userStyle->features());
 
     m_shadowDistributedRules.collectFeaturesTo(features);
 }
 
 } // namespace WebCore