[ash] Don't remove an item when associated window is dragged

ash/shelf/shelf_window_watcher.h

 // Copyright 2013 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_SHELF_SHELF_WINDOW_WATCHER_H_
 #define ASH_SHELF_SHELF_WINDOW_WATCHER_H_
 
 #include "ash/shelf/scoped_observer_with_duplicated_sources.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
@@ skipping 38 matching lines @@
    private:
     // aura::WindowObserver overrides:
     virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
 
     // Owned by Shell.
     ShelfWindowWatcher* window_watcher_;
 
     DISALLOW_COPY_AND_ASSIGN(RootWindowObserver);
   };
 
+  // Used to track windows that are removed. See description of
+  // ShelfWindowWatcher::StartObservingRemovedWindow() for more details.
+  class RemovedWindowObserver : public aura::WindowObserver {
+   public:
+    explicit RemovedWindowObserver(ShelfWindowWatcher* window_watcher);
+    virtual ~RemovedWindowObserver();
+
+   private:
+    // aura::WindowObserver overrides:
+    virtual void OnWindowParentChanged(aura::Window* window,
+                                       aura::Window* parent) OVERRIDE;
+    virtual void OnWindowDestroyed(aura::Window* window) OVERRIDE;
+
+    // Owned by Shell.
+    ShelfWindowWatcher* window_watcher_;
+
+    DISALLOW_COPY_AND_ASSIGN(RemovedWindowObserver);
+  };
+
   // Creates a LauncherItem for |window| that has LauncherItemDetails.
   void AddLauncherItem(aura::Window* window);
 
   // Removes a LauncherItem for |window|.
   void RemoveLauncherItem(aura::Window* window);
 
   // Adds observer to default container and ActivationClient of |root_window|.
   void OnRootWindowAdded(aura::Window* root_window);
 
   // Removes observer from ActivationClient of |root_window|.
   void OnRootWindowRemoved(aura::Window* root_window);
 
   // Updates the status of LauncherItem for |window|.
   void UpdateLauncherItemStatus(aura::Window* window, bool is_active);
 
   // Returns the index of LauncherItem associated with |window|.
   int GetLauncherItemIndexForWindow(aura::Window* window) const;
 
+  // Used when a window is removed. During the dragging a window may be removed
+  // and when the drag completes added back. When this happens we don't want to
+  // remove the shelf item. StartObservingRemovedWindow, if necessary, attaches
+  // an observer. When done, FinishObservingRemovedWindow() is invoked.
+  void StartObservingRemovedWindow(aura::Window* window);
+
+  // Stop observing |window| by RemovedWindowObserver and remove an item
+  // associated with |window|.
+  void FinishObservingRemovedWindow(aura::Window* window);
+
   // aura::client::ActivationChangeObserver overrides:
   virtual void OnWindowActivated(aura::Window* gained_active,
                                  aura::Window* lost_active) OVERRIDE;
 
   // aura::WindowObserver overrides:
   virtual void OnWindowAdded(aura::Window* window) OVERRIDE;
   virtual void OnWillRemoveWindow(aura::Window* window) OVERRIDE;
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
   virtual void OnWindowPropertyChanged(aura::Window* window,
                                        const void* key,
                                        intptr_t old) OVERRIDE;
 
   // gfx::DisplayObserver overrides:
   virtual void OnDisplayBoundsChanged(const gfx::Display& display) OVERRIDE;
   virtual void OnDisplayAdded(const gfx::Display& display) OVERRIDE;
   virtual void OnDisplayRemoved(const gfx::Display& old_display) OVERRIDE;
 
   // Owned by Shell.
   ShelfModel* model_;
   ShelfItemDelegateManager* item_delegate_manager_;
 
   RootWindowObserver root_window_observer_;
 
+  RemovedWindowObserver removed_window_observer_;
+
   // Holds all observed windows.
   ScopedObserver<aura::Window, aura::WindowObserver> observed_windows_;
 
   // Holds all observed root windows.
   ScopedObserver<aura::Window, aura::WindowObserver> observed_root_windows_;
 
+  // Holds removed windows that has an item from default container.
+  ScopedObserver<aura::Window, aura::WindowObserver> observed_removed_windows_;
+
   // Holds all observed activation clients.
   ScopedObserverWithDuplicatedSources<aura::client::ActivationClient,
       aura::client::ActivationChangeObserver> observed_activation_clients_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfWindowWatcher);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SHELF_SHELF_WINDOW_WATCHER_H_