1 // Copyright 2014 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef UI_VIEWS_WIDGET_WIDGET_REMOVALS_OBSERVER_H_ 6 #define UI_VIEWS_WIDGET_WIDGET_REMOVALS_OBSERVER_H_ 7 8 #include "ui/views/views_export.h" 9 10 namespace views { 11 12 class Widget; 13 class View; 14 15 // |WidgetRemovalsObserver| complements |WidgetObserver| with additional 16 // notifications. These include events occurring during tear down like view 17 // removal. For this reason, it is recommended that subclasses not also inherit 18 // from |View|. 19 class VIEWS_EXPORT WidgetRemovalsObserver { 20 public: 21 // Called immediately before a descendant view of |widget| is removed 22 // from this widget. Won't be called if the view is moved within the 23 // same widget, but will be called if it's moved to a different widget. 24 // Only called on the root of a view tree; it implies that all of the 25 // descendants of |view| will be removed. OnWillRemoveView(Widget * widget,View * view)26 virtual void OnWillRemoveView(Widget* widget, View* view) {} 27 28 protected: 29 virtual ~WidgetRemovalsObserver() = default; 30 }; 31 32 } // namespace views 33 34 #endif // UI_VIEWS_WIDGET_WIDGET_REMOVALS_OBSERVER_H_ 35