Make PPB_NetworkList_Private immutable.

ppapi/api/private/ppb_network_monitor_private.idl

+/* 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.
+ */
+
+/**
+ * This file defines the <code>PPB_NetworkMonitor_Private</code> interface.
+ */
+
+label Chrome {
+  M19 = 0.2
+};
+
+/**
+ * <code>PPB_NetworkMonitor_Callback</code> is a callback function
+ * type that is used to receive notifications about network
+ * configuration changes. The <code>network_list</code> passed to this
+ * callback is a <code>PPB_NetworkList_Private</code> resource that
+ * contains current configuration of network interfaces.
+ */
+typedef void PPB_NetworkMonitor_Callback([inout] mem_t user_data,
+                                         [in] PP_Resource network_list);
+
+
+/**
+ * The <code>PPB_NetworkMonitor_Private</code> provides access to
+ * notifications of network configuration changes.
+ */
+interface PPB_NetworkMonitor_Private {
+  /**
+   * Starts network change monitoring. The specified
+   * <code>callback</code> will be called on the main thread once
+   * after this method is called (to supply the initial network
+   * configuarion) and then later every time network configuration
+   * changes. Notifications are stopped when this method is called
+   * with <code>callback</code> set to NULL.

[dmichael (off chromium), 2012/02/24 18:04:11]

Hmm, I think I prefer wez's suggestion to return a PP_Resource. A plugin would
cancel the callbacks by releasing the resource. It might make it easier to scope
the lifetime of the backing object when you're implementing. That also makes it
possible to have multiple callback handlers, if that's something you want.

[Sergey Ulanov, 2012/02/24 18:25:11]

Done and also renamed it to Create(). In that case do we also need
IsNetworkMonitor() method?

[dmichael (off chromium), 2012/02/24 18:29:11]

Yes. I guess that's the downside; more boilerplate.

If this direction seems to annoying when you're implementing, feel free to
circle back and do it more like the other approach you had. I'm hoping this way
is a bit easier to implement (and maybe to use too, once you put a C++ wrapper
on it).

[Sergey Ulanov, 2012/02/24 18:54:34]

Done.
I actually like this approach more because it seems to be more consistent with
other interfaces.

+   *
+   * @param[in] callback The callback that will be called every time
+   * network configuration changes or NULL to stop network monitoring.
+   *
+   * @param[inout] user_data The data to be passed to the callback on
+   * each call.
+   *
+   * @return Returns an error-code in case of an error or PP_OK
+   * otherwise.
+   */
+  int32_t SetCallback([in] PP_Instance instance,

[Sergey Ulanov, 2012/02/23 02:17:28]

Also added this |instance| parameters, but not sure if we really need it here.

+                      [in] PPB_NetworkMonitor_Callback callback,
+                      [inout] mem_t user_data);
+
+};