Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/svg/SVGLength.cpp

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 122 matching lines @@
   return result;
 }
 
 SVGParsingError SVGLength::setValueAsString(const String& string) {
   if (string.isEmpty()) {
     m_value =
         CSSPrimitiveValue::create(0, CSSPrimitiveValue::UnitType::UserUnits);
     return SVGParseStatus::NoError;
   }
 
-  CSSParserContext svgParserContext(SVGAttributeMode, nullptr);
+  CSSParserContext* svgParserContext =
+      CSSParserContext::create(SVGAttributeMode);
   const CSSValue* parsed =
       CSSParser::parseSingleValue(CSSPropertyX, string, svgParserContext);
   if (!parsed || !parsed->isPrimitiveValue())
     return SVGParseStatus::ExpectedLength;
 
   const CSSPrimitiveValue* newValue = toCSSPrimitiveValue(parsed);
   if (!isSupportedCSSUnitType(newValue->typeWithCalcResolved()))
     return SVGParseStatus::ExpectedLength;
 
   m_value = newValue;
@@ skipping 113 matching lines @@
 
 float SVGLength::calculateDistance(SVGPropertyBase* toValue,
                                    SVGElement* contextElement) {
   SVGLengthContext lengthContext(contextElement);
   SVGLength* toLength = toSVGLength(toValue);
 
   return fabsf(toLength->value(lengthContext) - value(lengthContext));
 }
 
 }  // namespace blink