chromeos: makes it possible for windows to outlive WindowTreeClient

ui/aura/window.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 UI_AURA_WINDOW_H_
 #define UI_AURA_WINDOW_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 33 matching lines @@
 }
 
 namespace ui {
 class Layer;
 }
 
 namespace aura {
 
 class LayoutManager;
 class WindowDelegate;
+class WindowObserver;
 class WindowPort;
-class WindowObserver;
+class WindowPortForShutdown;
 class WindowTreeHost;
 
 // Defined in class_property.h (which we do not include)
 template<typename T>
 using WindowProperty = ui::ClassProperty<T>;
 
 namespace test {
 class WindowTestApi;
 }
 
@@ skipping 256 matching lines @@
   // Overrides from ui::PropertyHandler
   std::unique_ptr<ui::PropertyData> BeforePropertyChange(const void* key)
       override;
   void AfterPropertyChange(const void* key,
                            int64_t old_value,
                            std::unique_ptr<ui::PropertyData> data) override;
  private:
   friend class LayoutManager;
   friend class PropertyConverter;
   friend class WindowPort;
+  friend class WindowPortForShutdown;
   friend class WindowTargeter;
   friend class test::WindowTestApi;
 
   // Returns true if the mouse pointer at relative-to-this-Window's-origin
   // |local_point| can trigger an event for this Window.
   // TODO(beng): A Window can supply a hit-test mask to cause some portions of
   // itself to not trigger events, causing the events to fall through to the
   // Window behind.
   bool HitTest(const gfx::Point& local_point);
 
@@ skipping 91 matching lines @@
   void ConvertEventToTarget(ui::EventTarget* target,
                             ui::LocatedEvent* event) override;
 
   // Updates the layer name based on the window's name and id.
   void UpdateLayerName();
 
   // Window owns its corresponding WindowPort, but the ref is held as a raw
   // pointer in |port_| so that it can still be accessed during destruction.
   // This is important as deleting the WindowPort may result in trying to lookup
   // the WindowPort associated with the Window.
+  //
+  // NOTE: this value is reset for windows that exist when WindowTreeClient
+  // is deleted.
   std::unique_ptr<WindowPort> port_owner_;
   WindowPort* port_;
 
   // Bounds of this window relative to the parent. This is cached as the bounds
   // of the Layer and Window are not necessarily the same. In particular bounds
   // of the Layer are relative to the first ancestor with a Layer, where as this
   // is relative to the parent Window.
   gfx::Rect bounds_;
 
   WindowTreeHost* host_;
@@ skipping 29 matching lines @@
   bool ignore_events_;
 
   base::ObserverList<WindowObserver, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(Window);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_H_