Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/css/properties/CSSPropertyAPIRotate.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/CSSPropertyAPIRotate.h"
 
 #include "core/css/CSSValueList.h"
 #include "core/css/parser/CSSPropertyParserHelpers.h"
 #include "platform/RuntimeEnabledFeatures.h"
 
 namespace blink {
 
 const CSSValue* CSSPropertyAPIRotate::parseSingleValue(
     CSSParserTokenRange& range,
-    const CSSParserContext& context) {
+    const CSSParserContext* context) {
   DCHECK(RuntimeEnabledFeatures::cssIndependentTransformPropertiesEnabled());
   CSSValueList* list = CSSValueList::createSpaceSeparated();
 
   for (unsigned i = 0; i < 3; i++) {  // 3 dimensions of rotation
     CSSValue* dimension =
         CSSPropertyParserHelpers::consumeNumber(range, ValueRangeAll);
     if (!dimension) {
       if (i == 0)
         break;
       return nullptr;
     }
     list->append(*dimension);
   }
 
   CSSValue* rotation = CSSPropertyParserHelpers::consumeAngle(range);
   if (!rotation)
     return nullptr;
   list->append(*rotation);
 
   return list;
 }
 
 }  // namespace blink