[BackgroundSync] Fix lifetime issues with callbacks pointer in CallbackThreadAdapter

content/child/background_sync/background_sync_provider_thread_proxy.cc

Index: content/child/background_sync/background_sync_provider_thread_proxy.cc
diff --git a/content/child/background_sync/background_sync_provider_thread_proxy.cc b/content/child/background_sync/background_sync_provider_thread_proxy.cc
index 2361c4bd154e29e98d0201f5153add2a61e5c56e..378c45c2cd4cdaff6952a662aeabe040a9a7af30 100644
--- a/content/child/background_sync/background_sync_provider_thread_proxy.cc
+++ b/content/child/background_sync/background_sync_provider_thread_proxy.cc
@@ -40,7 +40,7 @@ class CallbackThreadAdapter : public blink::WebCallbacks<S, T> {
     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) {
@@ -49,7 +49,7 @@ class CallbackThreadAdapter : public blink::WebCallbacks<S, T> {
     WorkerTaskRunner::Instance()->PostTask(
         worker_thread_id_,
         base::Bind(&blink::WebCallbacks<S, T>::onError,
-                   base::Unretained(callbacks_.get()), error));
+                   base::Owned(callbacks_.release()), error));
   }
 
  private: