[Download Notification] Show preview if downloaded file is image

chrome/browser/download/notification/download_notification_browsertest.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 "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
@@ skipping 492 matching lines @@
   // Checks there is neither any download nor any notification.
   EXPECT_EQ(0u, GetMessageCenter()->GetVisibleNotifications().size());
   std::vector<content::DownloadItem*> downloads;
   GetDownloadManager(browser())->GetAllDownloads(&downloads);
   EXPECT_EQ(0u, downloads.size());
 
   // Checks the downloaded file doesn't exist.
   EXPECT_FALSE(base::PathExists(GetDownloadPath().Append(filename.BaseName())));
 }
 
+IN_PROC_BROWSER_TEST_F(DownloadNotificationTest, DownloadImageFile) {
+  GURL download_url(embedded_test_server()->GetURL(
+      "/downloads/image-octet-stream.png"));
+
+  content::DownloadTestObserverTerminal download_terminal_observer(
+      GetDownloadManager(browser()), 1u, /* wait_count */
+      content::DownloadTestObserver::ON_DANGEROUS_DOWNLOAD_IGNORE);
+
+  CreateDownloadForBrowserAndURL(browser(), download_url);
+
+  // Wait for the download completion.
+  download_terminal_observer.WaitForFinished();
+
+  // Waits for download completion.
+  while (GetNotification(notification_id())->image().IsEmpty()) {
+    NotificationUpdateObserver download_change_notification_observer;
+    download_change_notification_observer.Wait();
+  }
+}
+
 IN_PROC_BROWSER_TEST_F(DownloadNotificationTest,
                        CloseNotificationAfterDownload) {
   CreateDownload();
 
   // Requests to complete the download.
   ui_test_utils::NavigateToURL(
       browser(), GURL(net::URLRequestSlowDownloadJob::kFinishDownloadUrl));
 
   // Waits for download completion.
   while (download_item()->GetState() != content::DownloadItem::COMPLETE) {
@@ skipping 591 matching lines @@
   EXPECT_EQ(message_center::NOTIFICATION_TYPE_MULTIPLE,
             GetNotification(notification_id_user2_group)->type());
   EXPECT_EQ(2u,
             GetNotification(notification_id_user2_group)->items().size());
   // Normal notifications for user2.
   EXPECT_EQ(message_center::NOTIFICATION_TYPE_BASE_FORMAT,
             GetNotification(notification_id_user2_1)->type());
   EXPECT_EQ(message_center::NOTIFICATION_TYPE_BASE_FORMAT,
             GetNotification(notification_id_user2_2)->type());
 }