[RemotePlayback] Implement 'connecting' state

content/common/media/media_player_messages_android.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.
 
 // IPC messages for android media player.
 // Multiply-included message file, hence no include guard.
 
 #include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_message_macros.h"
@@ skipping 102 matching lines @@
 
 // Clank has connected to the remote device.
 IPC_MESSAGE_ROUTED2(MediaPlayerMsg_ConnectedToRemoteDevice,
                     int /* player_id */,
                     std::string /* remote_playback_message */)
 
 // Clank has disconnected from the remote device.
 IPC_MESSAGE_ROUTED1(MediaPlayerMsg_DisconnectedFromRemoteDevice,
                     int /* player_id */)
 
+// The remote playback has started.
+IPC_MESSAGE_ROUTED1(MediaPlayerMsg_RemotePlaybackStarted,
+                    int /* player_id */)
+
 // The remote playback device selection has been cancelled.
 IPC_MESSAGE_ROUTED1(MediaPlayerMsg_CancelledRemotePlaybackRequest,
                     int /* player_id */)
 
 // The availability of remote devices has changed
 IPC_MESSAGE_ROUTED2(MediaPlayerMsg_RemoteRouteAvailabilityChanged,
                     int /* player_id */,
                     bool /* routes_available */)
 
 // Messages for controlling the media playback in browser process ----------
@@ skipping 40 matching lines @@
 IPC_MESSAGE_ROUTED1(MediaPlayerHostMsg_RequestRemotePlayback,
                     int /* player_id */)
 
 // Control media playing on a remote device.
 IPC_MESSAGE_ROUTED1(MediaPlayerHostMsg_RequestRemotePlaybackControl,
                     int /* player_id */)
 
 // Stop playing media on a remote device.
 IPC_MESSAGE_ROUTED1(MediaPlayerHostMsg_RequestRemotePlaybackStop,
                     int /* player_id */)