Test URL instead of VirtualURL in [BVC isTabNativePage]

ios/chrome/browser/ui/browser_view_controller.mm

Index: ios/chrome/browser/ui/browser_view_controller.mm
diff --git a/ios/chrome/browser/ui/browser_view_controller.mm b/ios/chrome/browser/ui/browser_view_controller.mm
index 9b3b3afa3ff9a8cbe9cf40f7fc6d4b47c8adb8b0..9f8fc6bcf9695c0ba20d50a05e0976dc95cc02e7 100644
--- a/ios/chrome/browser/ui/browser_view_controller.mm
+++ b/ios/chrome/browser/ui/browser_view_controller.mm
@@ -2054,7 +2054,12 @@ class BrowserBookmarkModelBridge : public bookmarks::BookmarkModelObserver {
 
 // Whether the given tab's url begins with the chrome prefix.
 - (BOOL)isTabNativePage:(Tab*)tab {
-  return tab && tab.url.SchemeIs(kChromeUIScheme);
+  return tab && tab.webState && tab.webState->GetNavigationManager() &&

[Eugene But (OOO till 7-30), 2017/02/28 16:32:59]

Optional nit: How about using local variables and early returns?:

web::WebState* webState = tab.webState;
if (!webState)
  return NO;
web::NavigationManager* navigationManager = webState->GetNavigationManager();
if (!navigationManager)
  return NO;
web::NavigationItem* visibleItem = navigationManager->GetVisibleItem();
if (!visibleItem)
  return NO;
return visibleItem->GetURL().SchemeIs(kChromeUIScheme);

[Eugene But (OOO till 7-30), 2017/02/28 16:33:00]

|tab && | check is redundant, because if tab is nil, then |tab.webState| will be
nil.

[kkhorimoto, 2017/02/28 18:50:29]

Can we use GetWebClient()->IsAppSpecificURL() here?  It's checking against the
same scheme, but it'd be better not to duplicate code, especially since that
function is used as the source-of-truth of native vs. web pages from within the
web// layer.

[Olivier, 2017/03/01 14:46:14]

Done.

+         tab.webState->GetNavigationManager()->GetVisibleItem() &&
+         tab.webState->GetNavigationManager()
+             ->GetVisibleItem()
+             ->GetURL()
+             .SchemeIs(kChromeUIScheme);
 }
 
 - (void)expectNewForegroundTab {