Make JSONParser a pure interface.

chrome/browser/web_resource/chrome_web_resource_service.cc

 // Copyright 2015 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 "chrome/browser/web_resource/chrome_web_resource_service.h"
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 20 matching lines @@
           switches::kDisableBackgroundNetworking) {
 }
 
 ChromeWebResourceService::~ChromeWebResourceService() {
 }
 
 void ChromeWebResourceService::ParseJSON(
     const std::string& data,
     const SuccessCallback& success_callback,
     const ErrorCallback& error_callback) {
-  // SafeJsonParser releases itself on completion.
-  scoped_refptr<safe_json::SafeJsonParser> json_parser(
-      new safe_json::SafeJsonParser(data, success_callback,
-                                           error_callback));
-  json_parser->Start();
+  safe_json::SafeJsonParser::Parse(data, success_callback, error_callback);
 }