Added null safety for CSSParserContext in CSSPropertyLengthUtils.

third_party/WebKit/Source/core/css/properties/CSSPropertyLengthUtils.h

 // 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.
 
 #ifndef CSSPropertyLengthUtils_h
 #define CSSPropertyLengthUtils_h
 
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 #include "platform/wtf/Allocator.h"
 
 namespace blink {
 
 class CSSParserContext;
 class CSSParserTokenRange;
 class CSSValue;
 
 class CSSPropertyLengthUtils {
   STATIC_ONLY(CSSPropertyLengthUtils);
 
   static CSSValue* ConsumeMaxWidthOrHeight(
       CSSParserTokenRange&,
-      const CSSParserContext*,
+      const CSSParserContext&,
       CSSPropertyParserHelpers::UnitlessQuirk =
           CSSPropertyParserHelpers::UnitlessQuirk::kForbid);
   static CSSValue* ConsumeWidthOrHeight(
       CSSParserTokenRange&,
-      const CSSParserContext*,
+      const CSSParserContext&,
       CSSPropertyParserHelpers::UnitlessQuirk =
           CSSPropertyParserHelpers::UnitlessQuirk::kForbid);
 };
 
 }  // namespace blink
 
 #endif  // CSSPropertyLengthUtils_h