Refactor serialisation of openerId & openerNavigationIndex.

ios/web/web_state/web_state_impl_unittest.mm

 // Copyright 2014 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/web/web_state/web_state_impl.h"
 
 #include <stddef.h>
 
 #include <memory>
 
@@ skipping 227 matching lines @@
 }
 
 class WebStateTest : public web::WebTest {
  protected:
   void SetUp() override {
     web_state_.reset(new WebStateImpl(&browser_state_));
   }
 
   // Loads specified html page into WebState.
   void LoadHtml(std::string html) {
-    web_state_->GetNavigationManagerImpl().InitializeSession(nil, nil, NO, 0);
+    web_state_->GetNavigationManagerImpl().InitializeSession(nil, NO);
 
     // Use data: url for loading html page.
     std::string encoded_html;
     base::Base64Encode(html, &encoded_html);
     GURL url("data:text/html;charset=utf8;base64," + encoded_html);
     web::NavigationManager::WebLoadParams params(url);
     web_state_->GetNavigationManager()->LoadURLWithParams(params);
 
     // Trigger the load.
     web_state_->SetWebUsageEnabled(true);
@@ skipping 415 matching lines @@
       "</script>");
 
   base::test::ios::WaitUntilCondition(^{
     return message_received;
   });
   web_state_->RemoveScriptCommandCallback("test");
 }
 
 }  // namespace
 }  // namespace web