Initialize the message center as part of the testing browser process

chrome/browser/notifications/platform_notification_service_impl.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 "chrome/browser/notifications/platform_notification_service_impl.h"
 
 #include <utility>
 #include <vector>
 
 #include "base/metrics/histogram_macros.h"
@@ skipping 349 matching lines @@
   GetNotificationDisplayService(profile)->Close(NotificationCommon::PERSISTENT,
                                                 notification_id);
 }
 
 bool PlatformNotificationServiceImpl::GetDisplayedPersistentNotifications(
     BrowserContext* browser_context,
     std::set<std::string>* displayed_notifications) {
   DCHECK(displayed_notifications);
 
   Profile* profile = Profile::FromBrowserContext(browser_context);
-  if (!profile || profile->AsTestingProfile())
-    return false;  // Tests will not have a message center.
+  if (!profile)
+    return false;
+
+  NotificationDisplayService* display_service =
+      GetNotificationDisplayService(profile);
+  if (!display_service) {
+    // Tests might not have a browser process
+    DCHECK(profile->AsTestingProfile());
+    return false;
+  }
 
   // TODO(peter): Filter for persistent notifications only.
   return GetNotificationDisplayService(profile)->GetDisplayed(
       displayed_notifications);
 }
 
 void PlatformNotificationServiceImpl::OnClickEventDispatchComplete(
     content::PersistentNotificationStatus status) {
   UMA_HISTOGRAM_ENUMERATION(
       "Notifications.PersistentWebNotificationClickResult", status,
@@ skipping 115 matching lines @@
   }
 #endif
 
   return base::string16();
 }
 
 void PlatformNotificationServiceImpl::SetNotificationDisplayServiceForTesting(
     NotificationDisplayService* display_service) {
   test_display_service_ = display_service;
 }