Fix popup crash on ChromeOS.

chrome/browser/ui/views/message_center/web_notification_tray.cc

 // Copyright 2013 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/ui/views/message_center/web_notification_tray.h"
 
 #include "base/i18n/number_formatting.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 134 matching lines @@
 message_center::MessageCenter* WebNotificationTray::message_center() {
   return message_center_tray_->message_center();
 }
 
 bool WebNotificationTray::ShowPopups() {
   popup_collection_.reset(new message_center::MessagePopupCollection(
       NULL, message_center(), message_center_tray_.get(), false));
   return true;
 }
 
-void WebNotificationTray::HidePopups() { popup_collection_.reset(); }
+void WebNotificationTray::HidePopups() {
+  DCHECK(popup_collection_.get());
+
+  popup_collection_->MarkAllPopupsShown();
+  popup_collection_.reset();
+}
 
 bool WebNotificationTray::ShowMessageCenter() {
   message_center_delegate_ =
       new MessageCenterWidgetDelegate(this,
                                       message_center_tray_.get(),
                                       false,  // settings initally invisible
                                       GetPositionInfo());
 
   return true;
 }
@@ skipping 193 matching lines @@
   status_icon_menu_ = menu.get();
   status_icon->SetContextMenu(menu.Pass());
 }
 
 MessageCenterWidgetDelegate*
 WebNotificationTray::GetMessageCenterWidgetDelegateForTest() {
   return message_center_delegate_;
 }
 
 }  // namespace message_center