Oilpan: fix build after r183377.

Source/core/css/parser/BisonCSSParser-in.cpp

 /*
  * Copyright (C) 2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Nicholas Shanks <webkit@nickshanks.com>
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2012 Adobe Systems Incorporated. All rights reserved.
  * Copyright (C) 2012 Intel Corporation. All rights reserved.
  *
@@ skipping 666 matching lines @@
             return nullptr;
     }
 
     CSSParserString cssString;
     cssString.init(string);
     CSSValueID valueID = cssValueKeywordID(cssString);
 
     if (!valueID)
         return nullptr;
 
-    RefPtrWillBeRawPtr<CSSValue> value = nullptr;
     if (valueID == CSSValueInherit)
         return cssValuePool().createInheritedValue();
     if (valueID == CSSValueInitial)
         return cssValuePool().createExplicitInitialValue();
     if (CSSParserFastPaths::isValidKeywordPropertyAndValue(propertyId, valueID))
         return cssValuePool().createIdentifierValue(valueID);
     return nullptr;
 }
 
 template <typename CharType>
@@ skipping 1119 matching lines @@
     rule->setProperties(createStylePropertySet());
     clearProperties();
 
     StyleRuleViewport* result = rule.get();
     m_parsedRules.append(rule.release());
 
     return result;
 }
 
 }