Implement a callout widget for the active panel.

ash/wm/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_PANEL_LAYOUT_MANAGER_H_
 #define ASH_WM_PANEL_LAYOUT_MANAGER_H_
 #pragma once
 
 #include <list>
 
 #include "ash/ash_export.h"
 #include "ash/launcher/launcher_icon_observer.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "ui/aura/layout_manager.h"
 #include "ui/aura/window_observer.h"
 
 namespace aura {
 class Window;
 }
 
 namespace gfx {
 class Rect;
 }
 
+namespace views {
+class Widget;
+}
+
 namespace ash {
 class Launcher;
 
 namespace internal {
 
 // PanelLayoutManager is responsible for organizing panels within the
 // workspace. It is associated with a specific container window (i.e.
 // kShellWindowId_PanelContainer) and controls the layout of any windows
 // added to that container.
 //
@@ skipping 33 matching lines @@
       aura::Window* window, const void* key, intptr_t old) OVERRIDE;
 
  private:
   typedef std::list<aura::Window*> PanelList;
 
   // Called whenever the panel layout might change.
   void Relayout();
 
   // Called whenever the panel stacking order needs to be updated (e.g. focus
   // changes or a panel is moved).
-  void UpdateStacking(aura::Window* active_window);
+  void UpdateStacking(aura::Window* active_panel);
+
+  void UpdateCallout(aura::Window* active_panel);
 
   // Parent window associated with this layout manager.
   aura::Window* panel_container_;
   // Protect against recursive calls to Relayout().
   bool in_layout_;
   // Ordered list of unowned pointers to panel windows.
   PanelList panel_windows_;
   // The panel being dragged.
   aura::Window* dragged_panel_;
   // The launcher we are observing for launcher icon changes.
   Launcher* launcher_;
   // The last active panel. Used to maintain stacking even if no panels are
   // currently focused.
   aura::Window* last_active_panel_;
+  scoped_ptr<views::Widget> callout_widget_;
 
   DISALLOW_COPY_AND_ASSIGN(PanelLayoutManager);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_PANEL_LAYOUT_MANAGER_H_