Notify WidgetRemovalsObserver when RootView is removed

ui/views/widget/widget_unittest.cc

Index: ui/views/widget/widget_unittest.cc
diff --git a/ui/views/widget/widget_unittest.cc b/ui/views/widget/widget_unittest.cc
index c4e3a7c04a1623d8bb786bc6456164652ea883a1..0880a2b25ce4ff3ef531e1520dcd7f118e77b356 100644
--- a/ui/views/widget/widget_unittest.cc
+++ b/ui/views/widget/widget_unittest.cc
@@ -3649,6 +3649,18 @@ TEST_F(WidgetTest, WidgetRemovalsObserverCalled) {
   widget->RemoveRemovalsObserver(&removals_observer);
 }
 
+// Test that WidgetRemovalsObserver::OnWillRemoveView is called when deleting
+// the root view.
+TEST_F(WidgetTest, WidgetRemovalsObserverCalledWhenRemovingRootView) {
+  WidgetAutoclosePtr widget(CreateTopLevelPlatformWidget());
+  TestWidgetRemovalsObserver removals_observer;
+  widget->AddRemovalsObserver(&removals_observer);
+  views::View* root_view = widget->GetRootView();
+
+  widget.reset();
+  EXPECT_TRUE(removals_observer.DidRemoveView(root_view));
+}
+
 // Test that WidgetRemovalsObserver::OnWillRemoveView is called when moving
 // a view from one widget to another, but not when moving a view within
 // the same widget.