Test URL instead of VirtualURL in [BVC isTabNativePage]

ios/chrome/browser/ui/browser_view_controller.mm

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ios/chrome/browser/ui/browser_view_controller.h"
 
 #import <AssetsLibrary/AssetsLibrary.h>
 #import <MobileCoreServices/MobileCoreServices.h>
 #import <PassKit/PassKit.h>
 #import <Photos/Photos.h>
@@ skipping 2036 matching lines @@
                                           windowName:nil
                                               opener:nil
                                          openedByDOM:NO
                                              atIndex:position
                                         inBackground:NO];
   return tab;
 }
 
 // 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 {
   _expectingForegroundTab = YES;
 }
 
 - (UIImageView*)pageFullScreenOpenCloseAnimationView {
   CGRect viewBounds, remainder;
   CGRectDivide(self.view.bounds, &remainder, &viewBounds, StatusBarHeight(),
                CGRectMinYEdge);
@@ skipping 2957 matching lines @@
 
 - (UIView*)voiceSearchButton {
   return _voiceSearchButton;
 }
 
 - (id<LogoAnimationControllerOwner>)logoAnimationControllerOwner {
   return [self currentLogoAnimationControllerOwner];
 }
 
 @end