Implement automatic layout and stacking for docked windows

ash/wm/panels/panel_layout_manager.h

 // 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.
 
 #ifndef ASH_WM_PANELS_PANEL_LAYOUT_MANAGER_H_
 #define ASH_WM_PANELS_PANEL_LAYOUT_MANAGER_H_
 
 #include <list>
 
 #include "ash/ash_export.h"
@@ skipping 154 matching lines @@
   PanelList panel_windows_;
   // The panel being dragged.
   aura::Window* dragged_panel_;
   // The launcher we are observing for launcher icon changes.
   Launcher* launcher_;
   // The shelf layout manager being observed for visibility changes.
   ShelfLayoutManager* shelf_layout_manager_;
   // Tracks the visibility of the shelf. Defaults to false when there is no
   // shelf.
   bool shelf_hidden_;
-  // The last active panel. Used to maintain stacking even if no panels are
-  // currently focused.
+  // The last active panel. Used to maintain stacking order even if no panels
+  // are currently focused.
   aura::Window* last_active_panel_;
   base::WeakPtrFactory<PanelLayoutManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PanelLayoutManager);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_PANELS_PANEL_LAYOUT_MANAGER_H_