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

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIFontFamily.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/CSSPropertyAPIFontFamily.h"
 
 #include "core/css/CSSValueList.h"
 #include "core/css/properties/CSSPropertyFontUtils.h"
 
 class CSSParserContext;
 
 namespace blink {
 
 const CSSValue* CSSPropertyAPIFontFamily::parseSingleValue(
     CSSParserTokenRange& range,
-    const CSSParserContext*) {
+    const CSSParserContext&) {
   return CSSPropertyFontUtils::consumeFontFamily(range);
 }
 
 }  // namespace blink