Make CSSParserContext be garbage collected.

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

 // Copyright 2016 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/CSSPropertyAPIWillChange.h"
 
 #include "core/css/CSSValueList.h"
 #include "core/css/parser/CSSParserTokenRange.h"
 #include "core/css/parser/CSSPropertyParser.h"
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 
 namespace blink {
 
 const CSSValue* CSSPropertyAPIWillChange::parseSingleValue(
     CSSParserTokenRange& range,
-    const CSSParserContext& context) {
+    const CSSParserContext* context) {
   if (range.peek().id() == CSSValueAuto)
     return CSSPropertyParserHelpers::consumeIdent(range);
 
   CSSValueList* values = CSSValueList::createCommaSeparated();
   // Every comma-separated list of identifiers is a valid will-change value,
   // unless the list includes an explicitly disallowed identifier.
   while (true) {
     if (range.peek().type() != IdentToken)
       return nullptr;
     CSSPropertyID unresolvedProperty =
@@ skipping 30 matching lines @@
     if (range.atEnd())
       break;
     if (!CSSPropertyParserHelpers::consumeCommaIncludingWhitespace(range))
       return nullptr;
   }
 
   return values;
 }
 
 }  // namespace blink