Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/css/properties/CSSPropertyAPITextUnderlinePosition.cpp

 // Copyright 2017 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/properties/CSSPropertyAPITextUnderlinePosition.h"
 
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
 const CSSValue* CSSPropertyAPITextUnderlinePosition::parseSingleValue(
     CSSParserTokenRange& range,
-    const CSSParserContext& context) {
+    const CSSParserContext* context) {
   // auto | [ under || [ left | right ] ], but we only support auto | under
   // for now
   DCHECK(RuntimeEnabledFeatures::css3TextDecorationsEnabled());
   // auto | [ under || [ left | right ] ], but we only support auto | under
   // for now
   DCHECK(RuntimeEnabledFeatures::css3TextDecorationsEnabled());
   return CSSPropertyParserHelpers::consumeIdent<CSSValueAuto, CSSValueUnder>(
       range);
 }
 
 }  // namespace blink