[Media Router] Add DialMediaSinkService and DeviceDescriptionService

chrome/browser/media/router/discovery/dial/safe_dial_device_description_parser.h

 // 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.
 
 #ifndef CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DIAL_SAFE_DIAL_DEVICE_DESCRIPTION_PARSER_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DIAL_SAFE_DIAL_DEVICE_DESCRIPTION_PARSER_H_
 
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/ref_counted.h"
 #include "base/optional.h"
 #include "base/threading/thread_checker.h"
 #include "chrome/common/media_router/dial_device_description_parser.mojom.h"
 #include "content/public/browser/utility_process_mojo_client.h"
 
 namespace media_router {
 
 // SafeDialDeviceDescriptionParser parses the given device description XML file
 // safely via a utility process. This class runs on IO thread.
-class SafeDialDeviceDescriptionParser {
+class SafeDialDeviceDescriptionParser
+    : public base::RefCounted<SafeDialDeviceDescriptionParser> {
  public:
   // Callback function to be invoked when utility process finishes parsing
   // device description XML.
   // |success|: returns false if parsing fails.
   // |device_description|: device description object. Empty if parsing fails.
   using DeviceDescriptionCallback = chrome::mojom::DialDeviceDescriptionParser::
       ParseDialDeviceDescriptionCallback;
 
   SafeDialDeviceDescriptionParser();
 
   // Start parsing device description XML file in utility process.
   void Start(const std::string& xml_text,
              const DeviceDescriptionCallback& callback);
 
  private:
+  friend class base::RefCounted<SafeDialDeviceDescriptionParser>;
+
   ~SafeDialDeviceDescriptionParser();
 
   // See SafeDialDeviceDescriptionParser::DeviceDescriptionCallback
   void OnParseDeviceDescriptionComplete(
       chrome::mojom::DialDeviceDescriptionPtr device_description);
 
   // TODO(crbug.com/702766): Add an enum type describing why utility process
   // fails to parse device description xml.
   void OnParseDeviceDescriptionFailed();
 
   // Utility client used to send device description parsing task to the utility
   // process.
   std::unique_ptr<content::UtilityProcessMojoClient<
       chrome::mojom::DialDeviceDescriptionParser>>
       utility_process_mojo_client_;
 
   // Only accessed on the IO thread.
   DeviceDescriptionCallback device_description_callback_;
 
   base::ThreadChecker thread_checker_;
 
   DISALLOW_COPY_AND_ASSIGN(SafeDialDeviceDescriptionParser);
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DIAL_SAFE_DIAL_DEVICE_DESCRIPTION_PARSER_H_