Adds Window::MoveChildToFront, with surrounding changes.

views/widget/native_widget_wayland.cc

Index: views/widget/native_widget_wayland.cc
diff --git a/views/widget/native_widget_wayland.cc b/views/widget/native_widget_wayland.cc
index d85db33acc7dc5706ed43a20c626f633a598bda9..2be625ab699e4ac9fd7a95a32a535d009aebf7e4 100644
--- a/views/widget/native_widget_wayland.cc
+++ b/views/widget/native_widget_wayland.cc
@@ -319,12 +319,6 @@ void NativeWidgetWayland::SetSize(const gfx::Size& size) {
   SetBounds(new_alloc);
 }
 
-void NativeWidgetWayland::SetBoundsConstrained(const gfx::Rect& bounds,
-                                               Widget* other_widget) {
-  // TODO(dnicoara) Need to take into account |other_widget|.
-  SetBounds(bounds);
-}
-
 void NativeWidgetWayland::MoveAbove(gfx::NativeView native_view) {
   NOTIMPLEMENTED();
 }