[Media Router] Create MediaSinkServiceBase and make DialMediaSinkService inherit from it

chrome/browser/media/router/discovery/media_sink_service_base.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_MEDIA_SINK_SERVICE_BASE_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_MEDIA_SINK_SERVICE_BASE_H_
+
+#include <memory>
+#include <set>
+
+#include "base/gtest_prod_util.h"
+#include "base/timer/timer.h"
+#include "chrome/common/media_router/discovery/media_sink_internal.h"
+#include "chrome/common/media_router/discovery/media_sink_service.h"
+
+namespace media_router {
+
+class MediaSinkServiceBase : public MediaSinkService {
+ public:
+  explicit MediaSinkServiceBase(const OnSinksDiscoveredCallback& callback);
+  ~MediaSinkServiceBase() override;
+
+ protected:
+  void SetTimerForTest(std::unique_ptr<base::Timer> timer);
+
+  // Called when |finish_timer_| expires.
+  void OnFetchCompleted();
+
+  // Helper function to start |finish_timer_|.

[mark a. foltz, 2017/05/15 22:04:07]

Will all media sink services have the timer-based behavior?

[zhaobin, 2017/05/16 17:47:29]

Yes, plan to implement CastMediaSinkService with timer, similar to
DialMediaSinkService.

+  void StartTimer();
+
+  // Timer for finishing fetching.
+  std::unique_ptr<base::Timer> finish_timer_;
+
+  // Time out value for |finish_timer_|
+  int fetch_complete_timeout_secs_;
+
+  // Sorted sinks from current round of discovery.
+  std::set<MediaSinkInternal> current_sinks_;
+
+  // Sorted sinks sent to Media Router Provider in last FetchCompleted().
+  std::set<MediaSinkInternal> mrp_sinks_;
+
+ private:
+  friend class MediaSinkServiceBaseTest;
+  FRIEND_TEST_ALL_PREFIXES(MediaSinkServiceBaseTest,
+                           TestFetchCompleted_SameSink);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_MEDIA_SINK_SERVICE_BASE_H_