Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIFontVariationSettings.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/CSSPropertyAPIFontVariationSettings.h"
 
 #include "core/css/CSSFontVariationValue.h"
 #include "core/css/CSSValueList.h"
 #include "core/css/parser/CSSParserContext.h"
 #include "core/css/parser/CSSPropertyParserHelpers.h"
@@ skipping 25 matching lines @@
   double tagValue = 0;
   if (!CSSPropertyParserHelpers::consumeNumberRaw(range, tagValue))
     return nullptr;
   return CSSFontVariationValue::create(tag, clampTo<float>(tagValue));
 }
 
 }  // namespace
 
 const CSSValue* CSSPropertyAPIFontVariationSettings::parseSingleValue(
     CSSParserTokenRange& range,
-    const CSSParserContext& context) {
+    const CSSParserContext* context) {
   DCHECK(RuntimeEnabledFeatures::cssVariableFontsEnabled());
   if (range.peek().id() == CSSValueNormal)
     return CSSPropertyParserHelpers::consumeIdent(range);
   CSSValueList* variationSettings = CSSValueList::createCommaSeparated();
   do {
     CSSFontVariationValue* fontVariationValue = consumeFontVariationTag(range);
     if (!fontVariationValue)
       return nullptr;
     variationSettings->append(*fontVariationValue);
   } while (CSSPropertyParserHelpers::consumeCommaIncludingWhitespace(range));
   return variationSettings;
 }
 
 }  // namespace blink