Add View::AddedToWidget and RemovedFromWidget.

ui/views/view.cc

 // 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.
 
 #define _USE_MATH_DEFINES // For VC++ to get M_PI. This has to be first.
 
 #include "ui/views/view.h"
 
 #include <algorithm>
 #include <cmath>
@@ skipping 177 matching lines @@
   AddChildViewAt(view, child_count());
 }
 
 void View::AddChildViewAt(View* view, int index) {
   CHECK_NE(view, this) << "You cannot add a view as its own child";
   DCHECK_GE(index, 0);
   DCHECK_LE(index, child_count());
 
   // If |view| has a parent, remove it from its parent.
   View* parent = view->parent_;
-  ui::NativeTheme* old_theme = NULL;
+  ui::NativeTheme* old_theme = nullptr;
+  Widget* old_widget = nullptr;
   if (parent) {
     old_theme = view->GetNativeTheme();
+    old_widget = view->GetWidget();
     if (parent == this) {
       ReorderChildView(view, index);
       return;
     }
     parent->DoRemoveChildView(view, true, true, false, this);
   }
 
   // Sets the prev/next focus views.
   InitFocusSiblings(view, index);
 
@@ skipping 23 matching lines @@
     const ui::NativeTheme* new_theme = view->GetNativeTheme();
     if (new_theme != old_theme)
       view->PropagateNativeThemeChanged(new_theme);
   }
 
   ViewHierarchyChangedDetails details(true, this, view, parent);
 
   for (View* v = this; v; v = v->parent_)
     v->ViewHierarchyChangedImpl(false, details);
 
-  view->PropagateAddNotifications(details);
+  view->PropagateAddNotifications(details, widget && widget != old_widget);
 
   UpdateTooltip();
 
   if (widget) {
     RegisterChildrenForVisibleBoundsNotification(view);
 
     if (view->visible())
       view->SchedulePaint();
   }
 
@@ skipping 1254 matching lines @@
 void View::NativeViewHierarchyChanged() {
   FocusManager* focus_manager = GetFocusManager();
   if (accelerator_focus_manager_ != focus_manager) {
     UnregisterAccelerators(true);
 
     if (focus_manager)
       RegisterPendingAccelerators();
   }
 }
 
+void View::AddedToWidget() {}
+
+void View::RemovedFromWidget() {}
+
 // Painting --------------------------------------------------------------------
 
 void View::PaintChildren(const ui::PaintContext& context) {
   TRACE_EVENT1("views", "View::PaintChildren", "class", GetClassName());
   View::Views children = GetChildrenInZOrder();
   DCHECK_EQ(child_count(), static_cast<int>(children.size()));
   for (auto* child : children) {
     if (!child->layer())
       child->Paint(context);
   }
@@ skipping 393 matching lines @@
   if (update_focus_cycle) {
     View* next_focusable = view->next_focusable_view_;
     View* prev_focusable = view->previous_focusable_view_;
     if (prev_focusable)
       prev_focusable->next_focusable_view_ = next_focusable;
     if (next_focusable)
       next_focusable->previous_focusable_view_ = prev_focusable;
   }
 
   Widget* widget = GetWidget();
+  bool is_removed_from_widget = false;
   if (widget) {
     UnregisterChildrenForVisibleBoundsNotification(view);
     if (view->visible())
       view->SchedulePaint();
 
-    if (!new_parent || new_parent->GetWidget() != widget)
+    is_removed_from_widget = !new_parent || new_parent->GetWidget() != widget;
+    if (is_removed_from_widget)
       widget->NotifyWillRemoveView(view);
   }
 
   // Make sure the layers belonging to the subtree rooted at |view| get
   // removed.
   view->OrphanLayers();
   if (widget)
     widget->LayerTreeChanged();
 
-  view->PropagateRemoveNotifications(this, new_parent);
+  view->PropagateRemoveNotifications(this, new_parent, is_removed_from_widget);
   view->parent_ = nullptr;
 
   if (delete_removed_view && !view->owned_by_client_)
     view_to_be_deleted.reset(view);
 
 #if DCHECK_IS_ON()
   DCHECK(!iterating_);
 #endif
   children_.erase(i);
 
   if (update_tool_tip)
     UpdateTooltip();
 
   if (layout_manager_)
     layout_manager_->ViewRemoved(this, view);
 
   for (ViewObserver& observer : observers_)
     observer.OnChildViewRemoved(view, this);
 }
 
-void View::PropagateRemoveNotifications(View* old_parent, View* new_parent) {
+void View::PropagateRemoveNotifications(View* old_parent,
+                                        View* new_parent,
+                                        bool is_removed_from_widget) {
   {
     internal::ScopedChildrenLock lock(this);
-    for (auto* child : children_)
-      child->PropagateRemoveNotifications(old_parent, new_parent);
+    for (auto* child : children_) {
+      child->PropagateRemoveNotifications(old_parent, new_parent,
+                                          is_removed_from_widget);
+    }
   }
 
   ViewHierarchyChangedDetails details(false, old_parent, this, new_parent);
   for (View* v = this; v; v = v->parent_)
     v->ViewHierarchyChangedImpl(true, details);
+
+  if (is_removed_from_widget)
+    RemovedFromWidget();
 }
 
-void View::PropagateAddNotifications(
-    const ViewHierarchyChangedDetails& details) {
+void View::PropagateAddNotifications(const ViewHierarchyChangedDetails& details,
+                                     bool is_added_to_widget) {
   {
     internal::ScopedChildrenLock lock(this);
     for (auto* child : children_)
-      child->PropagateAddNotifications(details);
+      child->PropagateAddNotifications(details, is_added_to_widget);
   }
   ViewHierarchyChangedImpl(true, details);
+  if (is_added_to_widget)
+    AddedToWidget();
 }
 
 void View::PropagateNativeViewHierarchyChanged() {
   {
     internal::ScopedChildrenLock lock(this);
     for (auto* child : children_)
       child->PropagateNativeViewHierarchyChanged();
   }
   NativeViewHierarchyChanged();
 }
@@ skipping 553 matching lines @@
   // Message the RootView to do the drag and drop. That way if we're removed
   // the RootView can detect it and avoid calling us back.
   gfx::Point widget_location(event.location());
   ConvertPointToWidget(this, &widget_location);
   widget->RunShellDrag(this, data, widget_location, drag_operations, source);
   // WARNING: we may have been deleted.
   return true;
 }
 
 }  // namespace views