Move the CSS Device Adaptation @viewport rule support behind a runtime flag

Source/core/css/CSSParser.h

Index: Source/core/css/CSSParser.h
diff --git a/Source/core/css/CSSParser.h b/Source/core/css/CSSParser.h
index b29d5a6f9341d1ab75ce01ce8691a3c89c865bcf..ba1a1e2bce410e5c9d83d7718caf62f9e36063c6 100644
--- a/Source/core/css/CSSParser.h
+++ b/Source/core/css/CSSParser.h
@@ -404,11 +404,9 @@ public:
 
     void tokenToLowerCase(const CSSParserString& token);
 
-#if ENABLE(CSS_DEVICE_ADAPTATION)
     void markViewportRuleBodyStart() { m_inViewport = true; }
     void markViewportRuleBodyEnd() { m_inViewport = false; }
     StyleRuleBase* createViewportRule();
-#endif
 
     PassRefPtr<CSSPrimitiveValue> createPrimitiveNumericValue(CSSParserValue*);
     PassRefPtr<CSSPrimitiveValue> createPrimitiveStringValue(CSSParserValue*);
@@ -583,13 +581,11 @@ private:
     bool m_allowImportRules;
     bool m_allowNamespaceDeclarations;
 
-#if ENABLE(CSS_DEVICE_ADAPTATION)
     bool parseViewportProperty(CSSPropertyID propId, bool important);
     bool parseViewportShorthand(CSSPropertyID propId, CSSPropertyID first, CSSPropertyID second, bool important);
 
     bool inViewport() const { return m_inViewport; }
     bool m_inViewport;
-#endif
 
     int (CSSParser::*m_lexFunc)(void*);