[BackgroundSync] Fix lifetime issues with callbacks pointer in CallbackThreadAdapter

content/child/background_sync/background_sync_provider_thread_proxy.cc

 // Copyright 2015 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.
 
 #include "content/child/background_sync/background_sync_provider_thread_proxy.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/lazy_instance.h"
 #include "base/location.h"
@@ skipping 22 matching lines @@
       : worker_thread_id_(worker_thread_id) {
     callbacks_.reset(callbacks.release());
   }
 
   virtual void onSuccess(S* results) {
     // If the worker thread has been destroyed, then this task will be
     // silently discarded.
     WorkerTaskRunner::Instance()->PostTask(
         worker_thread_id_,
         base::Bind(&blink::WebCallbacks<S, T>::onSuccess,
-                   base::Unretained(callbacks_.get()), results));
+                   base::Owned(callbacks_.release()), results));
   }
 
   virtual void onError(T* error) {
     // If the worker thread has been destroyed, then this task will be
     // silently discarded.
     WorkerTaskRunner::Instance()->PostTask(
         worker_thread_id_,
         base::Bind(&blink::WebCallbacks<S, T>::onError,
-                   base::Unretained(callbacks_.get()), error));
+                   base::Owned(callbacks_.release()), error));
   }
 
  private:
   scoped_ptr<blink::WebCallbacks<S, T>> callbacks_;
   int worker_thread_id_;
 };
 
 LazyInstance<ThreadLocalPointer<BackgroundSyncProviderThreadProxy>>::Leaky
     g_sync_provider_tls = LAZY_INSTANCE_INITIALIZER;
 
@@ skipping 96 matching lines @@
     : main_thread_task_runner_(main_thread_task_runner),
       sync_provider_(sync_provider) {
   g_sync_provider_tls.Pointer()->Set(this);
 }
 
 BackgroundSyncProviderThreadProxy::~BackgroundSyncProviderThreadProxy() {
   g_sync_provider_tls.Pointer()->Set(nullptr);
 }
 
 }  // namespace content