dbus: Make Bus::GetManagedObjects skip unavailable services.

dbus/object_manager.h

Index: dbus/object_manager.h
diff --git a/dbus/object_manager.h b/dbus/object_manager.h
index 266b53eb9a0ac3d140d468114701af3ecad17ba9..9ec205a5886deaf47e0b5a9e9b64ed579e0f9549 100644
--- a/dbus/object_manager.h
+++ b/dbus/object_manager.h
@@ -145,7 +145,7 @@ public:
     virtual ~Interface() {}
 
     // Called by ObjectManager to create a Properties structure for the remote
-    // D-Bus object identified by |object_path| and accessibile through
+    // D-Bus object identified by |object_path| and accessible through
     // |object_proxy|. The D-Bus interface name |interface_name| is that passed
     // to RegisterInterface() by the implementation class.
     //
@@ -226,6 +226,10 @@ public:
   // a need to call this manually.
   void GetManagedObjects();
 
+  // Returns true if the service providing this object is currently available
+  // (i.e. its name has an owner).
+  bool ServiceIsAvailable();
+
   // Cleans up any match rules and filter functions added by this ObjectManager.
   // The Bus object will take care of this so you don't have to do it manually.
   //