Moved NavigationManagerImpl serialization out of CRWSessionController.

ios/chrome/browser/tabs/tab_model_unittest.mm

Index: ios/chrome/browser/tabs/tab_model_unittest.mm
diff --git a/ios/chrome/browser/tabs/tab_model_unittest.mm b/ios/chrome/browser/tabs/tab_model_unittest.mm
index 64a1ea0d3491e5dede090e68e52d5c2255f352ed..f4fad52c8f6b19226d8f697f43983d9ff4115d95 100644
--- a/ios/chrome/browser/tabs/tab_model_unittest.mm
+++ b/ios/chrome/browser/tabs/tab_model_unittest.mm
@@ -193,7 +193,8 @@ void RestoreSession(SessionWindowIOS* window) {
     SessionWindowIOS* window = [[SessionWindowIOS alloc] init];
     for (int i = 0; i < entries; i++) {
       NSString* windowName = [NSString stringWithFormat:@"window %d", i + 1];
-      [window addSession:CreateWebState(windowName)];
+      [window addSerializedSession:CreateWebState(windowName)
+                                       ->BuildSerializedNavigationManager()];
     }
     if (entries)
       [window setSelectedIndex:1];