Refactor serialisation of openerId & openerNavigationIndex.

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 98 matching lines @@
 
 // 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;
 @property(nonatomic, readonly) NSString* windowName;
 
-// ID associated with this tab, from the SessionManager.
+// ID associated with this tab.
 @property(nonatomic, readonly) NSString* tabId;
 
+// ID of the opener of this tab.
+@property(nonatomic, readonly) NSString* openerID;
+
+// NavigationIndex of the opener of this tab.
+@property(nonatomic, readonly) NSInteger openerNavigationIndex;
+
 // |YES| if snapshot overlay should load from the grey image cache.
 @property(nonatomic, assign) BOOL useGreyImageCache;
 
 // The Webstate associated with this Tab.
 @property(nonatomic, readonly) web::WebState* webState;
 
 @property(nonatomic, readonly) CRWWebController* webController;
 @property(nonatomic, readonly) PasswordController* passwordController;
 @property(nonatomic, readonly) BOOL canGoBack;
 @property(nonatomic, readonly) BOOL canGoForward;
@@ skipping 207 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_