chromeos: Add dbus MTPDClient.

chromeos/dbus/dbus_thread_manager.h

Index: chromeos/dbus/dbus_thread_manager.h
===================================================================
--- chromeos/dbus/dbus_thread_manager.h	(revision 150137)
+++ chromeos/dbus/dbus_thread_manager.h	(working copy)
@@ -46,6 +46,7 @@
 class IBusInputContextClient;
 class ImageBurnerClient;
 class IntrospectableClient;
+class MediaTransferProtocolDaemonClient;
 class ModemMessagingClient;
 class PowerManagerClient;
 class SessionManagerClient;
@@ -199,6 +200,12 @@
   // down.
   virtual IntrospectableClient* GetIntrospectableClient() = 0;
 
+  // Returns the media transfer protocol client, owned by DBusThreadManager.
+  // Do not cache this pointer and use it after DBusThreadManager is shut
+  // down.
+  virtual MediaTransferProtocolDaemonClient*
+      GetMediaTransferProtocolDaemonClient() = 0;
+
   // Returns the Modem Messaging client, owned by DBusThreadManager.
   // Do not cache this pointer and use it after DBusThreadManager is shut
   // down.