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

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIScale.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/CSSPropertyAPIScale.h"
 
 #include "core/css/CSSValueList.h"
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
 const CSSValue* CSSPropertyAPIScale::parseSingleValue(
     CSSParserTokenRange& range,
-    const CSSParserContext* context) {
+    const CSSParserContext& context) {
   DCHECK(RuntimeEnabledFeatures::cssIndependentTransformPropertiesEnabled());
 
   CSSValueID id = range.peek().id();
   if (id == CSSValueNone)
     return CSSPropertyParserHelpers::consumeIdent(range);
 
   CSSValue* scale =
       CSSPropertyParserHelpers::consumeNumber(range, ValueRangeAll);
   if (!scale)
     return nullptr;
   CSSValueList* list = CSSValueList::createSpaceSeparated();
   list->append(*scale);
   scale = CSSPropertyParserHelpers::consumeNumber(range, ValueRangeAll);
   if (scale) {
     list->append(*scale);
     scale = CSSPropertyParserHelpers::consumeNumber(range, ValueRangeAll);
     if (scale)
       list->append(*scale);
   }
 
   return list;
 }
 
 }  // namespace blink