Enforce that only one constrained window is displayed at once per tab.

chrome/browser/tab_contents/tab_contents_view_gtk.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_VIEW_GTK_H_
 #define CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_VIEW_GTK_H_
 
 #include <gtk/gtk.h>
 
 #include <vector>
@@ skipping 109 matching lines @@
   NotificationRegistrar registrar_;
 
   scoped_ptr<SadTabGtk> sad_tab_;
 
   FocusStoreGtk focus_store_;
 
   // Our UI for controlling popups (or NULL if no popup windows have been
   // opened). |popup_view_| is owned by the TabContents, not the view.
   BlockedPopupContainerViewGtk* popup_view_;
 
-  // Each individual UI for constrained dialogs currently displayed. The
-  // objects in this vector are owned by the TabContents, not the view.
-  std::vector<ConstrainedWindowGtk*> constrained_windows_;
+  // The UI for the constrained dialog currently displayed. This is owned by the
+  // TabContents, not the view.
+  ConstrainedWindowGtk* constrained_window_;
 
   // The helper object that handles drag destination related interactions with
   // GTK.
   scoped_ptr<WebDragDestGtk> drag_dest_;
 
   // Object responsible for handling drags from the page for us.
   scoped_ptr<TabContentsDragSource> drag_source_;
 
   // The size we want the tab contents view to be.  We keep this in a separate
   // variable because resizing in GTK+ is async.
   gfx::Size requested_size_;
 
   DISALLOW_COPY_AND_ASSIGN(TabContentsViewGtk);
 };
 
 #endif  // CHROME_BROWSER_TAB_CONTENTS_TAB_CONTENTS_VIEW_GTK_H_