Allow multiple object proxies to handle NameOwnerChanged

dbus/object_proxy.cc

Index: dbus/object_proxy.cc
===================================================================
--- dbus/object_proxy.cc	(revision 168554)
+++ dbus/object_proxy.cc	(working copy)
@@ -661,11 +661,11 @@
                                                 name_owner_changed_callback_,
                                                 released_signal));
       }
-      return DBUS_HANDLER_RESULT_HANDLED;
     }
   }
 
-  // Untrusted or uninteresting signal
+  // Always return unhandled to let other object proxies handle the same
+  // signal.
   return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 }