dbus: Rewrite ObjectProxy::ConnectToSignal with PostTaskAndReplyWithResult

dbus/object_proxy.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.
 
 #ifndef DBUS_OBJECT_PROXY_H_
 #define DBUS_OBJECT_PROXY_H_
 
 #include <dbus/dbus.h>
 
 #include <map>
@@ skipping 186 matching lines @@
   void RunResponseCallback(ResponseCallback response_callback,
                            ErrorCallback error_callback,
                            base::TimeTicks start_time,
                            DBusMessage* response_message);
 
   // Redirects the function call to OnPendingCallIsComplete().
   static void OnPendingCallIsCompleteThunk(DBusPendingCall* pending_call,
                                            void* user_data);
 
   // Helper function for ConnectToSignal().
-  void ConnectToSignalInternal(
-      const std::string& interface_name,
-      const std::string& signal_name,
-      SignalCallback signal_callback,
-      OnConnectedCallback on_connected_callback);
-
-  // Called when the object proxy is connected to the signal, or failed.
-  void OnConnected(OnConnectedCallback on_connected_callback,
-                   const std::string& interface_name,
-                   const std::string& signal_name,
-                   bool success);
+  bool ConnectToSignalInternal(const std::string& interface_name,
+                               const std::string& signal_name,
+                               SignalCallback signal_callback);
 
   // Handles the incoming request messages and dispatches to the signal
   // callbacks.
   DBusHandlerResult HandleMessage(DBusConnection* connection,
                                   DBusMessage* raw_message);
 
   // Runs the method. Helper function for HandleMessage().
   void RunMethod(base::TimeTicks start_time,
                  std::vector<SignalCallback> signal_callbacks,
                  Signal* signal);
@@ skipping 54 matching lines @@
 
   // Known name owner of the well-known bus name represnted by |service_name_|.
   std::string service_name_owner_;
 
   DISALLOW_COPY_AND_ASSIGN(ObjectProxy);
 };
 
 }  // namespace dbus
 
 #endif  // DBUS_OBJECT_PROXY_H_