Fix a bug where you couldn't bury a window in a tab that wasn't selected. This...

Fix a bug where you couldn't bury a window in a tab that wasn't selected. This was an issue with tmux gateways auto-hiding. It was revealed after merging 3.0.15 into master since both dealt with the problem of hiding the gateway after a delay, but only master had burying, and I adopted 3.0.15's way of handling the delay.

sources/WindowControllerInterface.h

@@ -21,6 +21,8 @@ typedef NS_ENUM(NSInteger, BroadcastMode) {
     BROADCAST_CUSTOM
 };
+@class iTermRestorableSession;
+
 // This is a very basic interface, which is sufficient for simulating a window
 // controller for instant replay.
 @protocol WindowControllerInterface <NSObject>
@@ -309,6 +311,8 @@ typedef NS_ENUM(NSInteger, BroadcastMode) {
                       encoding:(NSStringEncoding)optionalEncoding
                  forceEncoding:(BOOL)forceEncoding;
+- (iTermRestorableSession *)restorableSessionForSession:(PTYSession *)session;
+
 #pragma mark - Tmux
 // Returns the size of the window (in characters) that is the smallest width of

sources/iTermBuriedSessions.m

@@ -43,7 +43,7 @@
 }
 - (void)addBuriedSession:(PTYSession *)sessionToBury {
-    PseudoTerminal *windowController = (PseudoTerminal *)sessionToBury.textview.window.windowController;
+    id<iTermWindowController> windowController = (PseudoTerminal *)sessionToBury.delegate.parentWindow;
     iTermRestorableSession *restorableSession = [windowController restorableSessionForSession:sessionToBury];
     if (!restorableSession) {
         return;