Switch SupportsUserData uses to use unique_ptr.

components/offline_pages/core/downloads/download_notifying_observer.cc

 // Copyright 2016 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 "components/offline_pages/core/downloads/download_notifying_observer.h"
 
+#include "base/memory/ptr_util.h"
 #include "components/offline_pages/core/background/request_coordinator.h"
 #include "components/offline_pages/core/background/save_page_request.h"
 #include "components/offline_pages/core/client_policy_controller.h"
 #include "components/offline_pages/core/downloads/download_ui_adapter.h"
 #include "components/offline_pages/core/downloads/offline_page_download_notifier.h"
 
 namespace offline_pages {
 namespace {
 int kUserDataKey;  // Only address is used.
 }  // namespace
@@ skipping 12 matching lines @@
   return static_cast<DownloadNotifyingObserver*>(
       request_coordinator->GetUserData(&kUserDataKey));
 }
 
 // static
 void DownloadNotifyingObserver::CreateAndStartObserving(
     RequestCoordinator* request_coordinator,
     std::unique_ptr<OfflinePageDownloadNotifier> notifier) {
   DCHECK(request_coordinator);
   DCHECK(notifier.get());
-  DownloadNotifyingObserver* observer = new DownloadNotifyingObserver(
-      std::move(notifier), request_coordinator->GetPolicyController());
-  request_coordinator->AddObserver(observer);
-  // |request_coordinator| takes ownership of observer here.
-  request_coordinator->SetUserData(&kUserDataKey, observer);
+  std::unique_ptr<DownloadNotifyingObserver> observer =
+      base::WrapUnique(new DownloadNotifyingObserver(

[dewittj, 2017/04/28 19:02:19]

nit: rewrite this as:
auto observer =
base::MakeUnique<DownloadNotifyingObserver>(std::move(notifier)...)

[Avi (use Gerrit), 2017/04/28 21:12:51]

Sorry, but the constructor isn't public and therefore MakeUnique can't be used.

+          std::move(notifier), request_coordinator->GetPolicyController()));
+  request_coordinator->AddObserver(observer.get());
+  request_coordinator->SetUserData(&kUserDataKey, std::move(observer));
 }
 
 void DownloadNotifyingObserver::OnAdded(const SavePageRequest& request) {
   DCHECK(notifier_.get());
   if (!IsVisibleInUI(request.client_id()))
     return;
 
   // Calling Progress ensures notification is created in lieu of specific
   // Add/Create call.
   notifier_->NotifyDownloadProgress(DownloadUIItem(request));
@@ skipping 44 matching lines @@
     const SavePageRequest& request) {
   if (request.request_state() == SavePageRequest::RequestState::PAUSED)
     notifier_->NotifyDownloadPaused(DownloadUIItem(request));
   else if (request.request_state() == SavePageRequest::RequestState::AVAILABLE)
     notifier_->NotifyDownloadInterrupted(DownloadUIItem(request));
   else
     notifier_->NotifyDownloadProgress(DownloadUIItem(request));
 }
 
 }  // namespace offline_pages