[Media Router] Add DialMediaSinkService and DeviceDescriptionService

chrome/browser/media/router/dial_media_sink_service.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_DIAL_MEDIA_SINK_SERVICE_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_DIAL_MEDIA_SINK_SERVICE_H_
+
+#include <memory>
+
+#include "chrome/browser/extensions/api/dial/dial_registry.h"
+#include "chrome/browser/media/router/device_description_service.h"
+#include "chrome/browser/media/router/media_sink.h"
+#include "chrome/browser/media/router/media_sink_service.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace extensions {
+class DialAPI;
+}
+
+namespace net {
+class URLRequestContextGetter;
+}
+
+namespace media_router {
+
+class DialMediaSinkService
+    : public MediaSinkService,
+      public extensions::api::dial::DialRegistry::Observer,
+      public DeviceDescriptionService::Observer {
+ public:
+  DialMediaSinkService(const OnSinksDiscoveredCallback& callback,
+                       content::BrowserContext* browser_context);

[mark a. foltz, 2017/03/11 00:08:15]

Is this a profile-keyed service?

Note that we have one MR instance for both normal and incognito profiles - if
this is 1:1 with the Media Router, then make sure that no behavior is dependent
on the profile type.

[zhaobin, 2017/04/10 18:44:41]

We use profile to get request context for URL fetcher.

+  ~DialMediaSinkService() override;
+
+  // MediaSinkService implementation
+  void Start() override;
+  void AddSinkQuery(MediaSinksObserver* observer) override;
+  void RemoveSinkQuery(MediaSinksObserver* observer) override;
+
+ private:
+  using DialRegistry = extensions::api::dial::DialRegistry;
+
+  DialRegistry* dial_registry();
+  DeviceDescriptionService* description_service();
+
+  // api::dial::DialRegistry::Observer implementation
+  void OnDialDeviceEvent(const DialRegistry::DeviceList& devices) override;
+  void OnDialError(DialRegistry::DialErrorCode type) override;
+
+  // DeviceDescriptionService::Observer implementation.
+  void OnDeviceDescriptionAvailable(
+      const std::string& device_label,
+      const DialDeviceDescription& description) override;
+  void OnDeviceDescriptionFetchError(const std::string& device_label,
+                                     const std::string& error_message) override;
+
+  void OnDeviceDescription(const std::string& device_id);
+  void FetchCompleted();
+
+  // Device ids pending resolution
+  std::set<std::string> pending_device_labels_;
+
+  // Map of <sink id, mediaSink>
+  std::map<std::string, std::unique_ptr<MediaSink>> dial_sinks_;
+
+  // |dial_api_| lives in IO thread. It owns |dial_registry_|.
+  scoped_refptr<extensions::DialAPI> dial_api_;
+  DialRegistry* dial_registry_;

[mark a. foltz, 2017/03/11 00:08:15]

The DialRegistry should become refcounted, since I can't think of a reason to
have more than one per browser process; they will all see the same devices.

[zhaobin, 2017/03/28 13:36:59]

DialRegistry is a leaky singleton now. Raw pointer ok?

+
+  std::unique_ptr<DeviceDescriptionService> description_service_;
+  content::BrowserContext* browser_context_;
+  net::URLRequestContextGetter* request_context_;

[mark a. foltz, 2017/03/11 00:08:15]

This is usually passed directly to the URLFetcher before starting a request - is
there a reason to keep a pointer to it?

[zhaobin, 2017/04/10 18:44:42]

profile->GetRequestContext() should be called on UI thread. All
DialMediaSinkService functions except ctor is called on IO thread. Store this to
avoid posting tasks from IO thread to UI.

+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_DIAL_MEDIA_SINK_SERVICE_H_