Destroy NetworkChangeNotifier on the thread on which it is created

Previously NetworkChangeNotifier was created on UI thread, but could be 
destroyed on some other random thread, which could cause the crash in the 
linked bug.

Moved creation and destruction of the NetworkChangeNotifier to the 
network thread.

BUG=179476


Review URL: https://chromiumcodereview.appspot.com/12703020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@190549 0039d316-1c4b-4281-b951-d872f2087c98

remoting/host/remoting_me2me_host.cc

@@ -331,9 +331,6 @@ HostProcess::HostProcess(scoped_ptr<ChromotingHostContext> context,
 #endif  // defined(REMOTING_MULTI_PROCESS)
       ALLOW_THIS_IN_INITIALIZER_LIST(self_(this)),
       exit_code_out_(exit_code_out) {
-  // Create a NetworkChangeNotifier for use by the signalling connector.
-  network_change_notifier_.reset(net::NetworkChangeNotifier::Create());
-
   // Create the platform-specific curtain-mode implementation.
   // TODO(wez): Create this on the network thread?
   curtain_ = CurtainMode::Create(
@@ -913,6 +910,9 @@ void HostProcess::StartHost() {
       new DnsBlackholeChecker(context_->url_request_context_getter(),
                               talkgadget_prefix_));
 
+  // Create a NetworkChangeNotifier for use by the signaling connector.
+  network_change_notifier_.reset(net::NetworkChangeNotifier::Create());
+
   signaling_connector_.reset(new SignalingConnector(
       signal_strategy_.get(),
       context_->url_request_context_getter(),
@@ -1072,6 +1072,7 @@ void HostProcess::ShutdownOnNetworkThread() {
   host_change_notification_listener_.reset();
   signaling_connector_.reset();
   signal_strategy_.reset();
+  network_change_notifier_.reset();
 
   if (state_ == HOST_STOPPING_TO_RESTART) {
     StartHost();