Update first download notification correctly if there are multiple notifications

chrome/browser/download/notification/download_item_notification_unittest.cc

Index: chrome/browser/download/notification/download_item_notification_unittest.cc
diff --git a/chrome/browser/download/notification/download_item_notification_unittest.cc b/chrome/browser/download/notification/download_item_notification_unittest.cc
index 52c885a2f79cf125015d45e8a322af5e2707e1ef..30a497b0e52eaeafa06f51ac066e66b3c85ece9e 100644
--- a/chrome/browser/download/notification/download_item_notification_unittest.cc
+++ b/chrome/browser/download/notification/download_item_notification_unittest.cc
@@ -35,6 +35,26 @@ const base::FilePath::CharType kDownloadItemTargetPathString[] =
 
 namespace test {
 
+class MockMessageCenter : public message_center::FakeMessageCenter {
+ public:
+  MockMessageCenter() {}
+  ~MockMessageCenter() override {}
+
+  void AddVisibleNotification(message_center::Notification* notification) {
+    visible_notifications_.insert(notification);
+  }
+
+  const message_center::NotificationList::Notifications&
+      GetVisibleNotifications() override {
+    return visible_notifications_;
+  }
+
+ private:
+  message_center::NotificationList::Notifications visible_notifications_;
+
+  DISALLOW_COPY_AND_ASSIGN(MockMessageCenter);
+};
+
 class DownloadItemNotificationTest : public testing::Test {
  public:
   DownloadItemNotificationTest()
@@ -57,6 +77,10 @@ class DownloadItemNotificationTest : public testing::Test {
     download_notification_manager_.reset(
         new DownloadNotificationManagerForProfile(profile_, nullptr));
 
+    message_center_.reset(new MockMessageCenter());
+    download_notification_manager_->OverrideMessageCenterForTest(
+        message_center_.get());
+
     base::FilePath download_item_target_path(kDownloadItemTargetPathString);
     download_item_.reset(new NiceMock<content::MockDownloadItem>());
     ON_CALL(*download_item_, GetId()).WillByDefault(Return(12345));
@@ -135,6 +159,8 @@ class DownloadItemNotificationTest : public testing::Test {
     download_notification_manager_->OnNewDownloadReady(download_item_.get());
     download_item_notification_ =
         download_notification_manager_->items_[download_item_.get()];
+    message_center_->AddVisibleNotification(
+        download_item_notification_->notification_.get());
   }
 
   base::MessageLoopForUI message_loop_;
@@ -146,6 +172,7 @@ class DownloadItemNotificationTest : public testing::Test {
   scoped_ptr<NiceMock<content::MockDownloadItem>> download_item_;
   scoped_ptr<DownloadNotificationManagerForProfile>
       download_notification_manager_;
+  scoped_ptr<MockMessageCenter> message_center_;
   DownloadItemNotification* download_item_notification_;
 };