Moved NavigationManagerImpl serialization out of CRWSessionController.

ios/chrome/browser/crash_report/crash_restore_helper.mm

Index: ios/chrome/browser/crash_report/crash_restore_helper.mm
diff --git a/ios/chrome/browser/crash_report/crash_restore_helper.mm b/ios/chrome/browser/crash_report/crash_restore_helper.mm
index ad2b05f963ad6bad12ca8240ae26bedf3f1a5739..38a23ad85ca977c1c5c337a7ce9784890ad49b99 100644
--- a/ios/chrome/browser/crash_report/crash_restore_helper.mm
+++ b/ios/chrome/browser/crash_report/crash_restore_helper.mm
@@ -288,16 +288,18 @@ - (void)infoBarRemoved:(infobars::InfoBar*)infobar {
       loadWindowFromPath:[self sessionBackupPath]
          forBrowserState:[_tabModel browserState]];
   DCHECK(window);
-  if (!window.unclaimedSessions)
+  NSArray* sessions = window.sessions;
+  if (!sessions.count)
     return;
   sessions::TabRestoreService* const tabRestoreService =
       IOSChromeTabRestoreServiceFactory::GetForBrowserState(_browserState);
   tabRestoreService->LoadTabsFromLastSession();
 
-  while (window.unclaimedSessions) {
+  for (CRWNavigationManagerSerialization* session in sessions) {
+    web::WebState::CreateParams params(_browserState, session);
+    std::unique_ptr<web::WebState> webState = web::WebState::Create(params);
     // Add all tabs at the 0 position as the position is relative to an old
     // tabModel.
-    std::unique_ptr<web::WebStateImpl> webState = [window nextSession];
     tabRestoreService->CreateHistoricalTab(
         sessions::IOSLiveTab::GetForWebState(webState.get()), 0);
   }