dbus: adding PostTaskToDBusThreadAndReply

dbus/bus.h

Index: dbus/bus.h
diff --git a/dbus/bus.h b/dbus/bus.h
index 5cf73acd01ab856bddd64136c6a7c09d64fc2daa..03e2aa57a0a0ed79b2162083dda1492a94fb04db 100644
--- a/dbus/bus.h
+++ b/dbus/bus.h
@@ -511,6 +511,13 @@ class CHROME_DBUS_EXPORT Bus : public base::RefCountedThreadSafe<Bus> {
   // BLOCKING CALL.
   virtual void UnregisterObjectPath(const ObjectPath& object_path);
 
+  // Posts |task| to the task runner of the D-Bus thread. On completion, |reply|
+  // is posted to the origin thread.
+  virtual void PostTaskToDBusThreadAndReply(
+      const tracked_objects::Location& from_here,
+      const base::Closure& task,
+      const base::Closure& reply);
+
   // Posts the task to the task runner of the thread that created the bus.
   virtual void PostTaskToOriginThread(
       const tracked_objects::Location& from_here,