Revert of Changed CSSParserContext argument from * to & for null safety.

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIFontVariantLigatures.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/CSSPropertyAPIFontVariantLigatures.h"
 
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 #include "core/css/parser/FontVariantLigaturesParser.h"
 
 namespace blink {
 
 const CSSValue* CSSPropertyAPIFontVariantLigatures::parseSingleValue(
     CSSParserTokenRange& range,
-    const CSSParserContext& context) {
+    const CSSParserContext* context) {
   if (range.peek().id() == CSSValueNormal || range.peek().id() == CSSValueNone)
     return CSSPropertyParserHelpers::consumeIdent(range);
 
   FontVariantLigaturesParser ligaturesParser;
   do {
     if (ligaturesParser.consumeLigature(range) !=
         FontVariantLigaturesParser::ParseResult::ConsumedValue)
       return nullptr;
   } while (!range.atEnd());
 
   return ligaturesParser.finalizeValue();
 }
 
 }  // namespace blink