aura: Some changes in Window and Desktop.

ui/aura/window.h

 // Copyright (c) 2011 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 UI_AURA_WINDOW_H_
 #define UI_AURA_WINDOW_H_
 #pragma once
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/observer_list.h"
 #include "base/string16.h"
 #include "ui/base/ui_base_types.h"
 #include "ui/aura/aura_export.h"
 #include "ui/gfx/compositor/layer_delegate.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/rect.h"
 
 class SkCanvas;
 
 namespace ui {
@@ skipping 15 matching lines @@
 namespace internal {
 class FocusManager;
 class RootWindow;
 }
 
 // Aura window implementation. Interesting events are sent to the
 // WindowDelegate.
 // TODO(beng): resolve ownership.
 class AURA_EXPORT Window : public ui::LayerDelegate {
  public:
+  // Observers can listen to various events on the Windows.
+  class Observer {
+   public:
+    virtual void OnWindowClosing(Window* widget) {}

[sky, 2011/10/12 21:11:27]

Same comments as for Desktop::Observer.

+    virtual void OnWindowVisibilityChanged(Window* widget, bool visible) {}
+    virtual void OnWindowActivationChanged(Window* widget, bool active) {}
+  };
+
   typedef std::vector<Window*> Windows;
 
   explicit Window(WindowDelegate* delegate);
   virtual ~Window();
 
   void Init();
 
   // A type is used to identify a class of Windows and customize behavior such
   // as event handling and parenting. The value can be any of those in
   // window_types.h or a user defined value.
@@ skipping 93 matching lines @@
   void SetEventFilter(EventFilter* event_filter);
 
   // Handles a mouse event. Returns true if handled.
   bool OnMouseEvent(MouseEvent* event);
 
   // Handles a key event. Returns true if handled.
   bool OnKeyEvent(KeyEvent* event);
 
   WindowDelegate* delegate() { return delegate_; }
 
+  // Add/remove observer.
+  void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
+  bool HasObserver(Observer* observer);
+
   // When set to true, this Window will stop propagation of all events targeted
   // at Windows below it in the z-order, but only if this Window has children.
   // This is used to implement lock-screen type functionality where we do not
   // want events to be sent to running logged-in windows when the lock screen is
   // displayed.
   void set_stops_event_propagation(bool stops_event_propagation) {
     stops_event_propagation_ = stops_event_propagation;
   }
 
   // Returns true if the mouse pointer at the specified |point| can trigger an
@@ skipping 85 matching lines @@
 
   scoped_ptr<EventFilter> event_filter_;
   scoped_ptr<LayoutManager> layout_manager_;
 
   void* user_data_;
 
   // When true, events are not sent to windows behind this one in the z-order,
   // provided this window has children. See set_stops_event_propagation().
   bool stops_event_propagation_;
 
+  ObserverList<Observer> observers_;
+
   DISALLOW_COPY_AND_ASSIGN(Window);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_H_