Handle offline event in P2PSocketDispatcherHost

P2PSocketDispatcherHost is supposed to update network list even
when the system is offline (i.e. after last NIC is brought down).

Bug: 789125
Change-Id: Id732ca2e35f7ea435bc960fd37a2656b152fac32
Reviewed-on: https://chromium-review.googlesource.com/802237Reviewed-by: Paul Jensen <pauljensen@chromium.org>
Commit-Queue: Sergey Ulanov <sergeyu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524425}

content/browser/renderer_host/p2p/socket_dispatcher_host.cc

@@ -161,8 +161,11 @@ bool P2PSocketDispatcherHost::OnMessageReceived(const IPC::Message& message) {
 
 void P2PSocketDispatcherHost::OnNetworkChanged(
     net::NetworkChangeNotifier::ConnectionType type) {
-  if (type == net::NetworkChangeNotifier::CONNECTION_NONE)
+  // NetworkChangeNotifier always emits CONNECTION_NONE notification whenever
+  // network configuration changes. All other notifications can be ignored.
+  if (type != net::NetworkChangeNotifier::CONNECTION_NONE)
     return;
+
   // Notify the renderer about changes to list of network interfaces.
   network_list_task_runner_->PostTask(
       FROM_HERE,