Refactor serialisation of openerId & openerNavigationIndex.

ios/chrome/browser/tabs/tab_model.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/tabs/tab_model.h"
 
 #include <cstdint>
 #include <utility>
 #include <vector>
 
@@ skipping 103 matching lines @@
       base::Bind(&web::CertificatePolicyCache::ClearCertificatePolicies,
                  policy_cache),
       base::Bind(&RestoreCertificatePolicyCacheFromModel, policy_cache,
                  base::Unretained(web_state_list)));
 }
 
 // Internal helper function returning the opener for a given Tab by
 // checking the associated Tab tabId (should be removed once the opener
 // is passed to the insertTab:atIndex: and replaceTab:withTab: methods).
 Tab* GetOpenerForTab(id<NSFastEnumeration> tabs, Tab* tab) {
-  NSString* opener_id =
-      [tab navigationManager]->GetSessionController().openerId;
-  if (!opener_id)
+  if (!tab.openerID)
     return nullptr;
 
   for (Tab* currentTab in tabs) {
-    if ([opener_id isEqualToString:currentTab.tabId])
+    if ([tab.openerID isEqualToString:currentTab.tabId])
       return currentTab;
   }
 
   return nullptr;
 }
 
 }  // anonymous namespace
 
 @interface TabModelWebStateProxyFactory : NSObject<WebStateProxyFactory>
 @end
@@ skipping 996 matching lines @@
   web::NavigationManager::WebLoadParams params(URL);
   params.referrer = referrer;
   params.transition_type = ui::PAGE_TRANSITION_TYPED;
   [[tab webController] loadWithParams:params];
   [tab webController].webUsageEnabled = webUsageEnabled_;
   [self insertTab:tab atIndex:index opener:parentTab];
   return tab;
 }
 
 @end