[Media Router] Add DialMediaSinkService and DeviceDescriptionService

chrome/browser/media/router/discovery/dial/dial_media_sink_cache_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_DISCOVERY_DIAL_DIAL_MEDIA_SINK_CACHE_SERVICE_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DIAL_DIAL_MEDIA_SINK_CACHE_SERVICE_H_
+
+#include <map>
+#include <memory>
+
+#include "base/threading/thread_checker.h"
+#include "chrome/browser/media/router/discovery/dial/dial_device_data.h"
+#include "chrome/browser/media/router/discovery/dial/parsed_dial_device_description.h"
+#include "chrome/browser/media/router/discovery/media_sink_internal.h"
+
+namespace media_router {
+
+// Represents cached media sink.
+struct CachedDialMediaSink {
+  // The time the media sink was updated, in ms after the epoch.
+  base::Time last_update_time;
+
+  // The expiration time from the cache, in ms after the epoch.
+  base::Time expire_time;
+
+  // Underlying media sink object.
+  MediaSinkInternal sink;
+};
+
+class DialMediaSinkCacheService {
+ public:
+  DialMediaSinkCacheService();
+  virtual ~DialMediaSinkCacheService();
+
+  // Returns all media sinks with lastUpdateTime + aliveTimeout > currentTime
+  virtual std::vector<MediaSinkInternal> GetAliveSinks();
+
+  // Create a media sink from |device_data| and |description_data|. If sink
+  // exists in cache, update it if any field has changed since last update and
+  // update lastUpdateTime. If sink deos not exist, add it to cache.
+  void MayAddOrUpdateSink(const DialDeviceData& device_data,
+                          const ParsedDialDeviceDescription& description_data);
+
+ private:
+  friend class DialMediaSinkCacheServiceTest;
+
+  // Returns true if sink's lastUpdateTime + aliveTimeout > currentTime.
+  bool IsAlive(const CachedDialMediaSink& sink);
+
+  // Map of <sink id, CachedDialMediaSink>
+  std::map<std::string, CachedDialMediaSink> cached_sinks_;
+
+  base::ThreadChecker thread_checker_;
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DIAL_DIAL_MEDIA_SINK_CACHE_SERVICE_H_