Recognise variable names when parsing CSS property names

third_party/WebKit/Source/core/css/DOMWindowCSS.cpp

 /*
  * Copyright (C) 2012 Motorola Mobility 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 disclaimer.
  * 2. Redistributions in binary form must reproduce the above
@@ skipping 15 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "core/css/DOMWindowCSS.h"
 
 #include "core/css/CSSMarkup.h"
 #include "core/css/CSSPropertyMetadata.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/parser/CSSParser.h"
-#include "core/css/parser/CSSVariableParser.h"
 #include "wtf/text/StringBuilder.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 bool DOMWindowCSS::supports(const String& property, const String& value)
 {
     CSSPropertyID unresolvedProperty = unresolvedCSSPropertyID(property);
-    if (unresolvedProperty == CSSPropertyInvalid) {
-        if (CSSVariableParser::isValidVariableName(property)) {
-            MutableStylePropertySet* dummyStyle = MutableStylePropertySet::create(HTMLStandardMode);
-            return CSSParser::parseValueForCustomProperty(dummyStyle, "--valid", value, false, 0);
-        }
+    if (unresolvedProperty == CSSPropertyInvalid)
         return false;
+    if (unresolvedProperty == CSSPropertyVariable) {
+        MutableStylePropertySet* dummyStyle = MutableStylePropertySet::create(HTMLStandardMode);
+        return CSSParser::parseValueForCustomProperty(dummyStyle, "--valid", value, false, 0);

[ikilpatrick, 2016/08/29 16:30:59]

I assume once we have everything hooked up this will change from "--valid" to
property?

[Timothy Loh, 2016/08/30 03:57:18]

I'm not really sure why this is "--valid" (I guess it's been like that since
custom props were implemented), property should work just as well. I'll probably
have to add logic here for custom props 2 (if CSS.supports is supposed to
change)

     }
 
     ASSERT(CSSPropertyMetadata::isEnabledProperty(unresolvedProperty));
 
     // This will return false when !important is present
     MutableStylePropertySet* dummyStyle = MutableStylePropertySet::create(HTMLStandardMode);
     return CSSParser::parseValue(dummyStyle, unresolvedProperty, value, false, 0);
 }
 
 bool DOMWindowCSS::supports(const String& conditionText)
 {
     return CSSParser::parseSupportsCondition(conditionText);
 }
 
 String DOMWindowCSS::escape(const String& ident)
 {
     StringBuilder builder;
     serializeIdentifier(ident, builder);
     return builder.toString();
 }
 
 } // namespace blink