[CRD iOS] Don't attempt to connect to an offline host

remoting/ios/app/remoting_view_controller.mm

Index: remoting/ios/app/remoting_view_controller.mm
diff --git a/remoting/ios/app/remoting_view_controller.mm b/remoting/ios/app/remoting_view_controller.mm
index 1f28e5e65d82f1f94f86221002092efc3a545f70..443311a2225a3e80384744511864df6b2733203f 100644
--- a/remoting/ios/app/remoting_view_controller.mm
+++ b/remoting/ios/app/remoting_view_controller.mm
@@ -203,6 +203,13 @@ static CGFloat kHostInset = 5.f;
 
 - (void)didSelectCell:(HostCollectionViewCell*)cell
            completion:(void (^)())completionBlock {
+  if (![cell.hostInfo isOnline]) {
+    MDCSnackbarMessage* message = [[MDCSnackbarMessage alloc] init];
+    message.text = @"Host is offline.";

[nicholss, 2017/06/01 21:56:57]

Might be overkill but for now yeah, lets use it.

[Yuwei, 2017/06/01 22:06:49]

Okay. BTW this is what we do on Android #_#

+    [MDCSnackbarManager showMessage:message];
+    return;
+  }
+
   _client = [[RemotingClient alloc] init];
 
   [_remotingService.authentication