Add always-on-top property to app windows

ui/views/widget/widget_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 <algorithm>
 #include <set>
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 601 matching lines @@
     widget->StackAtTop();
     widget->IsClosed();
     widget->Close();
     widget->Show();
     widget->Hide();
     widget->Activate();
     widget->Deactivate();
     widget->IsActive();
     widget->DisableInactiveRendering();
     widget->SetAlwaysOnTop(true);
+    widget->IsAlwaysOnTop();
     widget->Maximize();
     widget->Minimize();
     widget->Restore();
     widget->IsMaximized();
     widget->IsFullscreen();
     widget->SetOpacity(0);
     widget->SetUseDragFrame(true);
     widget->FlashFrame(true);
     widget->IsVisible();
     widget->GetThemeProvider();
@@ skipping 1515 matching lines @@
   EXPECT_EQ(activate_result, MA_ACTIVATE);
 
   modal_dialog_widget->CloseNow();
   top_level_widget.CloseNow();
 }
 #endif
 #endif
 
 }  // namespace test
 }  // namespace views