Fix documentation for ObjectProxy::ConnectToSignal()

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 128 matching lines @@
   // be passed to the callback. If unsuccessful, the error callback will be
   // called and a pointer to ErrorResponse object will be passed to the error
   // callback if available, otherwise NULL will be passed.
   //
   // Must be called in the origin thread.
   virtual void CallMethodWithErrorCallback(MethodCall* method_call,
                                            int timeout_ms,
                                            ResponseCallback callback,
                                            ErrorCallback error_callback);
 
-  // Requests to connect to the signal from the remote object, replacing
-  // any previous |signal_callback| connected to that signal.
+  // Requests to connect to the signal from the remote object.
   //
   // |signal_callback| will be called in the origin thread, when the
   // signal is received from the remote object. As it's called in the
   // origin thread, |signal_callback| can safely reference objects in the
   // origin thread (i.e. UI thread in most cases).
   //
   // |on_connected_callback| is called when the object proxy is connected
   // to the signal, or failed to be connected, in the origin thread.
   //
+  // If a SignalCallback has already been registered for the given
+  // |interface_name| and |signal_name|, |signal_callback| will be
+  // added to the list of callbacks for |interface_name| and
+  // |signal_name|.
+  //
   // Must be called in the origin thread.
   virtual void ConnectToSignal(const std::string& interface_name,
                                const std::string& signal_name,
                                SignalCallback signal_callback,
                                OnConnectedCallback on_connected_callback);
 
   // Sets a callback for "NameOwnerChanged" signal. The callback is called on
   // the origin thread when D-Bus system sends "NameOwnerChanged" for the name
   // represented by |service_name_|.
   virtual void SetNameOwnerChangedCallback(NameOwnerChangedCallback callback);
@@ skipping 147 matching lines @@
   std::string service_name_owner_;
 
   std::set<DBusPendingCall*> pending_calls_;
 
   DISALLOW_COPY_AND_ASSIGN(ObjectProxy);
 };
 
 }  // namespace dbus
 
 #endif  // DBUS_OBJECT_PROXY_H_