Convert //sync from scoped_ptr to std::unique_ptr

sync/internal_api/attachments/attachment_store_frontend.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 "sync/internal_api/public/attachments/attachment_store_frontend.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/sequenced_task_runner.h"
 #include "sync/api/attachments/attachment.h"
 #include "sync/api/attachments/attachment_store_backend.h"
 
 namespace syncer {
 
 namespace {
 
 // NoOp is needed to bind base::Passed(backend) in AttachmentStoreFrontend dtor.
 // It doesn't need to do anything.
-void NoOp(scoped_ptr<AttachmentStoreBackend> backend) {
-}
+void NoOp(std::unique_ptr<AttachmentStoreBackend> backend) {}
 
 }  // namespace
 
 AttachmentStoreFrontend::AttachmentStoreFrontend(
-    scoped_ptr<AttachmentStoreBackend> backend,
+    std::unique_ptr<AttachmentStoreBackend> backend,
     const scoped_refptr<base::SequencedTaskRunner>& backend_task_runner)
     : backend_(std::move(backend)), backend_task_runner_(backend_task_runner) {
   DCHECK(backend_);
   DCHECK(backend_task_runner_.get());
 }
 
 AttachmentStoreFrontend::~AttachmentStoreFrontend() {
   DCHECK(backend_);
   // To delete backend post task that doesn't do anything, but binds backend
   // through base::Passed. This way backend will be deleted regardless whether
@@ skipping 66 matching lines @@
     AttachmentStore::Component component,
     const AttachmentStore::ReadMetadataCallback& callback) {
   DCHECK(CalledOnValidThread());
   backend_task_runner_->PostTask(
       FROM_HERE,
       base::Bind(&AttachmentStoreBackend::ReadMetadata,
                  base::Unretained(backend_.get()), component, callback));
 }
 
 }  // namespace syncer