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

base/observer_list_threadsafe.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_OBSERVER_LIST_THREADSAFE_H_
 #define BASE_OBSERVER_LIST_THREADSAFE_H_
 
 #include <unordered_map>
 
 #include "base/bind.h"
@@ skipping 124 matching lines @@
   void Notify(const tracked_objects::Location& from_here,
               Method m, Params&&... params) {
     Callback<void(ObserverType*)> method =
         Bind(&internal::Dispatcher<ObserverType, Method>::Run,
              m, std::forward<Params>(params)...);
 
     AutoLock lock(lock_);
     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)));
     }
   }
 
  private:
   friend class RefCountedThreadSafe<ObserverListThreadSafe<ObserverType>>;
 
   struct NotificationData {
     NotificationData(const tracked_objects::Location& from_here_in,
                      const Callback<void(ObserverType*)>& method_in)
         : from_here(from_here_in), method(method_in) {}
@@ skipping 46 matching lines @@
 
   // Notification being dispatched on the current thread.
   ThreadLocalPointer<const NotificationData> tls_current_notification_;
 
   DISALLOW_COPY_AND_ASSIGN(ObserverListThreadSafe);
 };
 
 }  // namespace base
 
 #endif  // BASE_OBSERVER_LIST_THREADSAFE_H_