Make CSSParserContext be garbage collected.

third_party/WebKit/Source/core/css/StyleSheetContentsFuzzer.cpp

 // Copyright 2016 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/StyleSheetContents.h"
 
 #include "platform/testing/BlinkFuzzerTestSupport.h"
 #include "wtf/text/WTFString.h"
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
-  blink::CSSParserContext context(blink::HTMLStandardMode, nullptr);
+  blink::CSSParserContext* context =
+      blink::CSSParserContext::create(blink::HTMLStandardMode);
   blink::StyleSheetContents* styleSheet =
       blink::StyleSheetContents::create(context);
   styleSheet->parseString(String::fromUTF8WithLatin1Fallback(
       reinterpret_cast<const char*>(data), size));
   return 0;
 }
 
 extern "C" int LLVMFuzzerInitialize(int* argc, char*** argv) {
   blink::InitializeBlinkFuzzTest(argc, argv);
   return 0;
 }