Rewrite base::Bind into base::BindOnce on trivial cases in base

base/observer_list_threadsafe.h

Index: base/observer_list_threadsafe.h
diff --git a/base/observer_list_threadsafe.h b/base/observer_list_threadsafe.h
index 9e6e347ea08b61c05581c0152be8fa13b6ee5fbf..c175c1787da6a0304b1d9063e9fbe3736d5d1a4b 100644
--- a/base/observer_list_threadsafe.h
+++ b/base/observer_list_threadsafe.h
@@ -142,8 +142,8 @@ class ObserverListThreadSafe
     for (const auto& observer : observers_) {
       observer.second->PostTask(
           from_here,
-          Bind(&ObserverListThreadSafe<ObserverType>::NotifyWrapper, this,
-               observer.first, NotificationData(from_here, method)));
+          BindOnce(&ObserverListThreadSafe<ObserverType>::NotifyWrapper, this,
+                   observer.first, NotificationData(from_here, method)));
     }
   }