Make GetDisplayedNotifications asynchronous.

content/test/mock_platform_notification_service.cc

 // Copyright 2014 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/test/mock_platform_notification_service.h"
 
 #include "base/guid.h"
 #include "base/strings/nullable_string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "content/public/browser/browser_thread.h"
@@ skipping 62 matching lines @@
 }
 
 void MockPlatformNotificationService::ClosePersistentNotification(
     BrowserContext* browser_context,
     const std::string& notification_id) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   persistent_notifications_.erase(notification_id);
 }
 
-bool MockPlatformNotificationService::GetDisplayedNotifications(
+void MockPlatformNotificationService::GetDisplayedNotifications(
     BrowserContext* browser_context,
-    std::set<std::string>* displayed_notifications) {
+    const DisplayedNotificationsCallback& callback) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
-  DCHECK(displayed_notifications);
+  auto displayed_notifications = base::MakeUnique<std::set<std::string>>();
 
   for (const auto& kv : persistent_notifications_)
     displayed_notifications->insert(kv.first);
 
-  return true;
+  BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(callback, base::Passed(&displayed_notifications),
+                 true /* supports_synchronization */));
 }
 
 void MockPlatformNotificationService::SimulateClick(
     const std::string& title,
     int action_index,
     const base::NullableString16& reply) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
   const auto notification_id_iter = notification_id_map_.find(title);
   if (notification_id_iter == notification_id_map_.end())
@@ skipping 84 matching lines @@
     non_persistent_notifications_.erase(non_persistent_iter);
   }
 }
 
 blink::mojom::PermissionStatus MockPlatformNotificationService::CheckPermission(
     const GURL& origin) {
   return blink::mojom::PermissionStatus::GRANTED;
 }
 
 }  // namespace content