Initialize network connection type

Previously it was always initialized to CONNECTION_NONE, so if
the first transition is to CONNECTION_NONE, it would not send out
a notification.

Bug: 883208
Change-Id: I583003a8d2d7160c88165a72194ca84eb9f42925
Reviewed-on: https://chromium-review.googlesource.com/c/1256285Reviewed-by: Misha Efimov <mef@chromium.org>
Commit-Queue: Paul Jensen <pauljensen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596042}

net/base/network_change_notifier_linux.cc

@@ -63,6 +63,7 @@ NetworkChangeNotifierLinux::Thread::~Thread() {
 
 void NetworkChangeNotifierLinux::Thread::Init() {
   address_tracker_->Init();
+  last_type_ = GetCurrentConnectionType();
   dns_config_service_ = DnsConfigService::CreateSystemService();
   dns_config_service_->WatchConfig(
       base::Bind(&NetworkChangeNotifier::SetDnsConfig));