Separate @viewport from other RuleSet construction.

third_party/WebKit/Source/core/css/StyleSheetContents.h

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2012 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 83 matching lines @@
   void setHasSyntacticallyValidCSSHeader(bool isValidCss);
   bool hasSyntacticallyValidCSSHeader() const {
     return m_hasSyntacticallyValidCSSHeader;
   }
 
   void setHasFontFaceRule() { m_hasFontFaceRule = true; }
   bool hasFontFaceRule() const { return m_hasFontFaceRule; }
   void findFontFaceRules(
       HeapVector<Member<const StyleRuleFontFace>>& fontFaceRules);
 
+  void setHasViewportRule() { m_hasViewportRule = true; }
+  bool hasViewportRule() const { return m_hasViewportRule; }
+
   void parserAddNamespace(const AtomicString& prefix, const AtomicString& uri);
   void parserAppendRule(StyleRuleBase*);
 
   void clearRules();
 
   // Rules other than @import.
   const HeapVector<Member<StyleRuleBase>>& childRules() const {
     return m_childRules;
   }
   const HeapVector<Member<StyleRuleImport>>& importRules() const {
@@ skipping 80 matching lines @@
   HeapVector<Member<StyleRuleBase>> m_childRules;
   using PrefixNamespaceURIMap = HashMap<AtomicString, AtomicString>;
   PrefixNamespaceURIMap m_namespaces;
   AtomicString m_defaultNamespace;
   WeakMember<CSSStyleSheetResource> m_referencedFromResource;
 
   bool m_hasSyntacticallyValidCSSHeader : 1;
   bool m_didLoadErrorOccur : 1;
   bool m_isMutable : 1;
   bool m_hasFontFaceRule : 1;
+  bool m_hasViewportRule : 1;
   bool m_hasMediaQueries : 1;
   bool m_hasSingleOwnerDocument : 1;
   bool m_isUsedFromTextCache : 1;
 
   CSSParserContext m_parserContext;
 
   HeapHashSet<WeakMember<CSSStyleSheet>> m_loadingClients;
   HeapHashSet<WeakMember<CSSStyleSheet>> m_completedClients;
 
   Member<RuleSet> m_ruleSet;
   String m_sourceMapURL;
 };
 
 }  // namespace blink
 
 #endif