Make CSSPropertyParser::parseSingleValue return a const CSSValue*

third_party/WebKit/Source/core/css/cssom/CSSStyleValue.cpp

 // Copyright 2015 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/cssom/CSSStyleValue.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptValue.h"
 #include "bindings/core/v8/ToV8.h"
 #include "core/StylePropertyShorthand.h"
@@ skipping 12 matching lines @@
     CSSPropertyID propertyID = cssPropertyID(propertyName);
     if (propertyID == CSSPropertyInvalid) {
         exceptionState.throwTypeError("Invalid property name");
         return ScriptValue::createNull(scriptState);
     }
     if (isShorthandProperty(propertyID)) {
         exceptionState.throwTypeError("Parsing shorthand properties is not supported");
         return ScriptValue::createNull(scriptState);
     }
 
-    CSSValue* cssValue = CSSParser::parseSingleValue(propertyID, value, strictCSSParserContext());
+    const CSSValue* cssValue = CSSParser::parseSingleValue(propertyID, value, strictCSSParserContext());
     if (!cssValue)
         return ScriptValue::createNull(scriptState);
 
     CSSStyleValueVector styleValueVector = StyleValueFactory::cssValueToStyleValueVector(propertyID, *cssValue);
     if (styleValueVector.size() != 1) {
         // TODO(meade): Support returning a CSSStyleValueOrCSSStyleValueSequence
         // from this function.
         return ScriptValue::createNull(scriptState);
     }
 
     v8::Local<v8::Value> wrappedValue = toV8(styleValueVector[0], scriptState->context()->Global(), scriptState->isolate());
     return ScriptValue(scriptState, wrappedValue);
 }
 
 } // namespace blink