[ios] Removed CookieStoreIOS::UnSynchronize.

ios/net/cookies/cookie_store_ios.mm

Index: ios/net/cookies/cookie_store_ios.mm
diff --git a/ios/net/cookies/cookie_store_ios.mm b/ios/net/cookies/cookie_store_ios.mm
index a6d844cd8d59121fbfadaf42fe317ddcc6c3a402..c34383b99c7f0c8ce05d16d32ce3ed414375552d 100644
--- a/ios/net/cookies/cookie_store_ios.mm
+++ b/ios/net/cookies/cookie_store_ios.mm
@@ -327,24 +327,10 @@ std::unique_ptr<CookieStoreIOS> CookieStoreIOS::CreateCookieStore(
 }
 
 // static
-void CookieStoreIOS::SwitchSynchronizedStore(CookieStoreIOS* old_store,
-                                             CookieStoreIOS* new_store) {
-  DCHECK(new_store);
-  DCHECK_NE(new_store, old_store);
-  if (old_store)
-    old_store->SetSynchronizedWithSystemStore(false);
-  new_store->SetSynchronizedWithSystemStore(true);
-}
-
-// static
 void CookieStoreIOS::NotifySystemCookiesChanged() {
   NotificationTrampoline::GetInstance()->NotifyCookiesChanged();
 }
 
-void CookieStoreIOS::UnSynchronize() {
-  SetSynchronizedWithSystemStore(false);
-}
-
 void CookieStoreIOS::SetMetricsEnabled() {
   static CookieStoreIOS* g_cookie_store_with_metrics = nullptr;
   DCHECK(!g_cookie_store_with_metrics || g_cookie_store_with_metrics == this)