Support unit-less lengths for white-list of properties only.

Source/core/css/parser/CSSParserMode.h

 /*
  * Copyright (C) 2012 Adobe Systems Incorporated. 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 53 matching lines @@
     return mode == UASheetMode;
 }
 
 inline bool isInternalPropertyAndValueParsingEnabledForMode(CSSParserMode mode)
 {
     return mode == HTMLAttributeMode || mode == UASheetMode;
 }
 
 inline bool isUnitLessLengthParsingEnabledForMode(CSSParserMode mode)
 {
-    return mode == HTMLQuirksMode || mode == HTMLAttributeMode || mode == SVGAttributeMode;
+    return mode == HTMLAttributeMode || mode == SVGAttributeMode;
 }
 
 inline bool isCSSViewportParsingEnabledForMode(CSSParserMode mode)
 {
     return mode == CSSViewportRuleMode;
 }
 
 inline bool isUseCounterEnabledForMode(CSSParserMode mode)
 {
     // We don't count the UA style sheet in our statistics.
@@ skipping 50 matching lines @@
     ContentSecurityPolicyDisposition m_shouldCheckContentSecurityPolicy;
 
     UseCounter* m_useCounter;
 };
 
 const CSSParserContext& strictCSSParserContext();
 
 };
 
 #endif // CSSParserMode_h