Unprefix the @viewport rule of CSS Device Adaptation spec

Source/core/css/CSSViewportRule.h

 /*
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  * Copyright (C) 2012 Apple 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:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
@@ skipping 29 matching lines @@
 class StyleRuleCSSStyleDeclaration;
 
 class CSSViewportRule: public CSSRule {
 public:
     static PassRefPtr<CSSViewportRule> create(StyleRuleViewport* viewportRule, CSSStyleSheet* sheet)
     {
         return adoptRef(new CSSViewportRule(viewportRule, sheet));
     }
     ~CSSViewportRule();
 
-    virtual CSSRule::Type type() const OVERRIDE { return WEBKIT_VIEWPORT_RULE; }
+    virtual CSSRule::Type type() const OVERRIDE { return VIEWPORT_RULE; }
     virtual String cssText() const OVERRIDE;
     virtual void reattach(StyleRuleBase*) OVERRIDE;
     virtual void reportMemoryUsage(MemoryObjectInfo*) const OVERRIDE;
 
     CSSStyleDeclaration* style() const;
 
 private:
     CSSViewportRule(StyleRuleViewport*, CSSStyleSheet*);
 
     RefPtr<StyleRuleViewport> m_viewportRule;
     mutable RefPtr<StyleRuleCSSStyleDeclaration> m_propertiesCSSOMWrapper;
 };
 
 } // namespace WebCore
 
 #endif // CSSViewportRule_h