Inject JSON parsing in WebResource as a callback rather than inheritance

chrome/browser/web_resource/chrome_web_resource_service.h

-// 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.
-
-#ifndef CHROME_BROWSER_WEB_RESOURCE_CHROME_WEB_RESOURCE_SERVICE_H_
-#define CHROME_BROWSER_WEB_RESOURCE_CHROME_WEB_RESOURCE_SERVICE_H_
-
-#include "base/macros.h"
-#include "components/web_resource/web_resource_service.h"
-
-// Chrome implementation of WebResourceService.
-// ChromeWebResourceService safely parses JSON out of process.
-class ChromeWebResourceService : public web_resource::WebResourceService {
- public:
-  ChromeWebResourceService(PrefService* prefs,
-                           const GURL& web_resource_server,
-                           bool apply_locale_to_url,
-                           const char* last_update_time_pref_name,
-                           int start_fetch_delay_ms,
-                           int cache_update_delay_ms);
-
- protected:
-  ~ChromeWebResourceService() override;
-
- private:
-  // WebResourceService implementation:
-  void ParseJSON(const std::string& data,
-                 const SuccessCallback& success_callback,
-                 const ErrorCallback& error_callback) override;
-
-  DISALLOW_COPY_AND_ASSIGN(ChromeWebResourceService);
-};
-
-#endif  // CHROME_BROWSER_WEB_RESOURCE_CHROME_WEB_RESOURCE_SERVICE_H_