Change return type of Tab -navigationManager.

ios/chrome/browser/tabs/tab.h

 // 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.
 
 #ifndef IOS_CHROME_BROWSER_TABS_TAB_H_
 #define IOS_CHROME_BROWSER_TABS_TAB_H_
 
 #import <UIKit/UIKit.h>
 
 #include <memory>
@@ skipping 39 matching lines @@
 class ChromeBrowserState;
 }
 
 namespace sessions {
 class SerializedNavigationEntry;
 struct SessionTab;
 }
 
 namespace web {
 class NavigationItem;
+class NavigationManager;
 class NavigationManagerImpl;
 struct Referrer;
 class WebState;
 }
 
 // Notification sent by a Tab when it starts to load a new URL. This
 // notification must only be used for crash reporting as it is also sent for
 // pre-rendered tabs.
 extern NSString* const kTabUrlStartedLoadingNotificationForCrashReporting;
 
@@ skipping 167 matching lines @@
 
 // Dismisses all modals owned by the tab.
 - (void)dismissModals;
 
 // Opens StoreKit modal to download a native application identified with
 // |appId|.
 - (void)openAppStore:(NSString*)appId;
 
 // Returns the NavigationManager for this tab's WebState. Requires WebState to
 // be populated. Can return null.
-- (web::NavigationManagerImpl*)navigationManager;
+// TODO(crbug.com/620465): remove navigationManagerImpl once Tab no longer uses
+// nor exposes private ios/web/ API.
+- (web::NavigationManager*)navigationManager;
+- (web::NavigationManagerImpl*)navigationManagerImpl;
 
 // Update the tab's history by replacing all previous navigations with
 // |navigations|.
 - (void)replaceHistoryWithNavigations:
             (const std::vector<sessions::SerializedNavigationEntry>&)navigations
                          currentIndex:(NSInteger)currentIndex;
 
 // Navigate forwards or backwards to |item|.
 - (void)goToItem:(const web::NavigationItem*)item;
 - (void)reload;
@@ skipping 84 matching lines @@
 
 // Called when this tab is hidden.
 - (void)wasHidden;
 
 // Evaluates U2F result.
 - (void)evaluateU2FResultFromURL:(const GURL&)url;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_TABS_TAB_H_