Add mojo-based support for media device-change notifications.

content/renderer/media/user_media_client_impl_unittest.cc

Index: content/renderer/media/user_media_client_impl_unittest.cc
diff --git a/content/renderer/media/user_media_client_impl_unittest.cc b/content/renderer/media/user_media_client_impl_unittest.cc
index 296e6ba01d9b6ce0a675fcb412ba9872691bb1a0..2bc5cbd3a6f4955e2f802645c5e3aceadbf6c593 100644
--- a/content/renderer/media/user_media_client_impl_unittest.cc
+++ b/content/renderer/media/user_media_client_impl_unittest.cc
@@ -75,6 +75,13 @@ class MockMediaDevicesDispatcherHost
     callback.Run(result);
   }
 
+  MOCK_METHOD3(SubscribeDeviceChangeNotifications,
+               void(MediaDeviceType type,
+                    uint32_t subscription_id,
+                    const url::Origin& security_origin));
+  MOCK_METHOD2(UnsubscribeDeviceChangeNotifications,
+               void(MediaDeviceType type, uint32_t subscription_id));
+
   ::mojom::MediaDevicesDispatcherHostPtr CreateInterfacePtrAndBind() {
     return binding_.CreateInterfacePtrAndBind();
   }