Fix setting css-wide keywords on registered custom properties

third_party/WebKit/Source/core/css/parser/CSSParserImpl.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/css/parser/CSSParserImpl.h"
 
 #include "core/css/CSSCustomIdentValue.h"
 #include "core/css/CSSCustomPropertyDeclaration.h"
 #include "core/css/CSSKeyframesRule.h"
 #include "core/css/CSSStyleSheet.h"
@@ skipping 63 matching lines @@
     bool important,
     const CSSParserContext& context,
     bool isAnimationTainted) {
   CSSParserImpl parser(context);
   CSSTokenizer tokenizer(value);
   parser.consumeVariableValue(tokenizer.tokenRange(), propertyName, important,
                               isAnimationTainted);
   bool didParse = false;
   bool didChange = false;
   if (!parser.m_parsedProperties.isEmpty()) {
-    if (registry) {
+    const CSSCustomPropertyDeclaration* parsedDeclaration =
+        toCSSCustomPropertyDeclaration(parser.m_parsedProperties[0].value());
+    if (parsedDeclaration->value() && registry) {
       const PropertyRegistry::Registration* registration =
           registry->registration(propertyName);
       // TODO(timloh): This is a bit wasteful, we parse the registered property
       // to validate but throw away the result.
       if (registration &&
           !registration->syntax().parse(tokenizer.tokenRange(),
                                         isAnimationTainted)) {
         return MutableStylePropertySet::SetResult{didParse, didChange};
       }
     }
@@ skipping 882 matching lines @@
     else
       return nullptr;  // Parser error, invalid value in keyframe selector
     if (range.atEnd())
       return result;
     if (range.consume().type() != CommaToken)
       return nullptr;  // Parser error
   }
 }
 
 }  // namespace blink