Added |lastCommittedURL| and |visibleURL| to Tab's interface.

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 88 matching lines @@
     : NSObject<CRWWebDelegate, ManageAccountsDelegate, SadTabTabHelperDelegate>
 
 // Browser state associated with this Tab.
 @property(nonatomic, readonly) ios::ChromeBrowserState* browserState;
 
 // TODO(crbug.com/546208): Eliminate this; replace calls with either visible URL
 // or last committed URL, depending on the specific use case.
 // Do not add new calls to this method.
 @property(nonatomic, readonly) const GURL& url;
 
+// Returns the URL of the last committed NavigationItem for this Tab.
+@property(nonatomic, readonly) const GURL& lastCommittedURL;
+
+// Returns the URL of the visible NavigationItem for this Tab.
+@property(nonatomic, readonly) const GURL& visibleURL;
+
 // The Passkit Dialog provider used to show the UI to download a passkit object.
 @property(nonatomic, assign) id<PassKitDialogProvider> passKitDialogProvider;
 
 // The current title of the tab.
 @property(nonatomic, readonly) NSString* title;
 
 // Original page title or nil if the page did not provide one.
 @property(nonatomic, readonly) NSString* originalTitle;
 
 @property(nonatomic, readonly) NSString* urlDisplayString;
@@ skipping 180 matching lines @@
 // Evaluates U2F result.
 - (void)evaluateU2FResultFromURL:(const GURL&)url;
 
 // Cancels prerendering. It is an error to call this on anything except a
 // prerender tab (where |isPrerenderTab| is set to YES).
 - (void)discardPrerender;
 
 @end
 
 #endif  // IOS_CHROME_BROWSER_TABS_TAB_H_