Fix Ash notification updates

ash/system/web_notification/web_notification_tray_unittest.cc

 // Copyright (c) 2012 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 "ash/system/web_notification/web_notification_tray.h"
 
 #include <vector>
 
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/system_tray_item.h"
@@ skipping 39 matching lines @@
     notification_ids_.insert(id);
     tray->AddNotification(id,
                           ASCIIToUTF16("Test Web Notification"),
                           ASCIIToUTF16("Notification message body."),
                           ASCIIToUTF16("www.test.org"),
                           "" /* extension id */);
   }
 
   void RemoveNotification(WebNotificationTray* tray, const std::string& id) {
     tray->RemoveNotification(id);
+    notification_ids_.erase(id);
   }
 
   bool HasNotificationId(const std::string& id) {
     return notification_ids_.find(id) != notification_ids_.end();
   }
 
  private:
   std::set<std::string> notification_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(TestDelegate);
@@ skipping 24 matching lines @@
   EXPECT_FALSE(delegate->HasNotificationId("test_id2"));
   EXPECT_EQ(1, tray->GetNotificationCount());
 
   // Removing the last notification should hide the bubble.
   delegate->RemoveNotification(tray, "test_id1");
   EXPECT_EQ(0, tray->GetNotificationCount());
   EXPECT_TRUE(tray->notification_bubble() == NULL);
 }
 
 }  // namespace ash