Change overview mode to so that docked panel windows are not grouped together.

ash/wm/overview/transparent_activate_window_button.cc

 // Copyright 2014 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/wm/overview/transparent_activate_window_button.h"
 
 #include <vector>
 
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
@@ skipping 115 matching lines @@
   // Explicitly specify the display so that the window doesn't change root
   // windows and cause the z-order of the transparent overlays to be updated.
   window->SetBoundsInScreen(bounds, display);
 }
 
 void TransparentActivateWindowButton::SendFocusAlert() const {
   event_handler_widget_->GetContentsView()->
       NotifyAccessibilityEvent(ui::AX_EVENT_FOCUS, true);
 }
 
-void TransparentActivateWindowButton::StackAbove(
-    TransparentActivateWindowButton* activate_button) {
-  aura::Window* this_window = event_handler_widget_->GetNativeWindow();
-  aura::Window* other_window = activate_button->event_handler_widget_->
-      GetNativeWindow();
-  this_window->parent()->StackChildAbove(this_window, other_window);
-}
-
 }  // namespace ash