Set OmniboxPopup incognito property before view creation

This CL sets the incognito property of the OmniboxPopupViewController
before the view is created when passed to the mediator as the property
is used in viewDidLoad.

Bug: 797239
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Change-Id: I0db9d1754ea32d6d1a6c7cde5d2638f187da5fd3
Reviewed-on: https://chromium-review.googlesource.com/842723Reviewed-by: Stepan Khapugin <stkhapugin@chromium.org>
Commit-Queue: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#526068}

ios/chrome/browser/ui/omnibox/popup/omnibox_popup_coordinator.mm

@@ -52,6 +52,7 @@
       [[OmniboxPopupMediator alloc] initWithFetcher:std::move(imageFetcher)
                                            delegate:_popupView.get()];
   self.popupViewController = [[OmniboxPopupViewController alloc] init];
+  self.popupViewController.incognito = self.browserState->IsOffTheRecord();
 
   self.mediator.incognito = self.browserState->IsOffTheRecord();
   self.mediator.consumer = self.popupViewController;
@@ -61,7 +62,6 @@
 
   self.popupViewController.imageRetriever = self.mediator;
   self.popupViewController.delegate = self.mediator;
-  self.popupViewController.incognito = self.browserState->IsOffTheRecord();
 
   _popupView->SetMediator(self.mediator);
 }