Minor fixes for WidgetRemovalsObserver::OnWillRemoveView

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index 45467ab23dbfc0fdbf68fdd9ad1ef9532bd20e64..f2c93c2a082e5a73f437b7a828ef2036090c4133 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -1803,7 +1803,6 @@ void View::DoRemoveChildView(View* view,
       UnregisterChildrenForVisibleBoundsNotification(view);
       if (view->visible())
         view->SchedulePaint();
-      GetWidget()->NotifyWillRemoveView(view);
     }
 
     view->PropagateRemoveNotifications(this, new_parent);
@@ -1824,6 +1823,9 @@ void View::DoRemoveChildView(View* view,
 }
 
 void View::PropagateRemoveNotifications(View* old_parent, View* new_parent) {
+  if (GetWidget())
+    GetWidget()->NotifyWillRemoveView(this);

[sky, 2016/01/25 21:22:14]

Doing this here means we have to constantly to determine the widget, which isn't
going to change. Also, I think OnWillRemoveView should only be sent if removed,
and not added to a different view in the same widget.

[dmazzoni, 2016/01/25 21:44:27]

OK, moved to a separate helper that takes the widget as an argument.
Good point, though it seems like it should be called if it gets reparented to a
new widget, right?

I added a test for those cases.

+
   for (int i = 0, count = child_count(); i < count; ++i)
     child_at(i)->PropagateRemoveNotifications(old_parent, new_parent);