Remove owned views from AXAuraObjCache when widget is deleted.

ui/views/accessibility/ax_aura_obj_cache.cc

Index: ui/views/accessibility/ax_aura_obj_cache.cc
diff --git a/ui/views/accessibility/ax_aura_obj_cache.cc b/ui/views/accessibility/ax_aura_obj_cache.cc
index 8d5937b39c1b702d1a927af9cf1f82d05c738015..1b09df379ac6ff3c4837a6c3cbccf9cdad0aad32 100644
--- a/ui/views/accessibility/ax_aura_obj_cache.cc
+++ b/ui/views/accessibility/ax_aura_obj_cache.cc
@@ -49,8 +49,19 @@ void AXAuraObjCache::Remove(View* view) {
   RemoveInternal(view, view_to_id_map_);
 }
 
+void AXAuraObjCache::RemoveViewSubtree(View* view) {
+  Remove(view);
+  for (int i = 0; i < view->child_count(); ++i)
+    RemoveViewSubtree(view->child_at(i));
+}
+
 void AXAuraObjCache::Remove(Widget* widget) {
   RemoveInternal(widget, widget_to_id_map_);
+
+  // When an entire widget is deleted, it doesn't always send a notification
+  // on each of its views, so we need to explore them recursively.
+  if (widget->GetRootView())
+    RemoveViewSubtree(widget->GetRootView());
 }
 
 void AXAuraObjCache::Remove(aura::Window* window) {