[Media Router] Use DialMediaSinkService in MediaRouterMojoImpl

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

 // Copyright (c) 2012 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_REGISTRY_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DIAL_DIAL_REGISTRY_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 57 matching lines @@
   // pass a reference of |observer| to allow it to notify on DIAL device events.
   // This class does not take ownership of observer.
   virtual void RegisterObserver(Observer* observer);
   virtual void UnregisterObserver(Observer* observer);
 
   // Called by the DIAL API to try to kickoff a discovery if there is not one
   // already active.
   bool DiscoverNow();
 
   // Starts and stops periodic discovery.  Periodic discovery is done when there
   // are registered event listeners.

[Kevin M, 2017/05/03 21:07:27]

Virtual for testing?

[zhaobin, 2017/05/04 23:52:36]

Yes...

-  void StartPeriodicDiscovery();
-  void StopPeriodicDiscovery();
+  virtual void StartPeriodicDiscovery();
+  virtual void StopPeriodicDiscovery();
 
   // Returns the URL of the device description for the device identified by
   // |label|, or an empty GURL if no such device exists.
   GURL GetDeviceDescriptionURL(const std::string& label) const;
 
   // Adds a device directly to the registry as if it was discovered.  For tests
   // only.  Note that if discovery is actually started, this device will be
   // removed by PruneExpiredDevices().
   void AddDeviceForTest(const DialDeviceData& device_data);
 
@@ skipping 115 matching lines @@
                            TestRemovingListenerDoesNotClearList);
   FRIEND_TEST_ALL_PREFIXES(DialRegistryTest, TestNetworkEventConnectionLost);
   FRIEND_TEST_ALL_PREFIXES(DialRegistryTest,
                            TestNetworkEventConnectionRestored);
   DISALLOW_COPY_AND_ASSIGN(DialRegistry);
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_DISCOVERY_DIAL_DIAL_REGISTRY_H_