Reorder the NativeViews attached to a view via kViewHostKey according to the position of the view

ui/aura/window.cc

Index: ui/aura/window.cc
diff --git a/ui/aura/window.cc b/ui/aura/window.cc
index c1f7487309be081a743a3e1696c245d952f05976..5160bf6c34fbd23f33c5f943d2a8fa9b325b5ba3 100644
--- a/ui/aura/window.cc
+++ b/ui/aura/window.cc
@@ -340,6 +340,12 @@ void Window::StackChildAbove(Window* child, Window* target) {
   StackChildRelativeTo(child, target, STACK_ABOVE);
 }
 
+void Window::StackChildAtBottom(Window* child) {
+  if (children_.size() <= 1 || child == children_.front())
+    return;  // At the bottom already.
+  StackChildBelow(child, children_.front());
+}
+
 void Window::StackChildBelow(Window* child, Window* target) {
   StackChildRelativeTo(child, target, STACK_BELOW);
 }