Add always-on-top property to app windows

ui/views/widget/native_widget_win.cc

Index: ui/views/widget/native_widget_win.cc
diff --git a/ui/views/widget/native_widget_win.cc b/ui/views/widget/native_widget_win.cc
index afdd6d80d5f5a192d95b053aa2640e627dc0eae2..dacb1a65873c7c312d467396acd7891c3bfeeb37 100644
--- a/ui/views/widget/native_widget_win.cc
+++ b/ui/views/widget/native_widget_win.cc
@@ -334,6 +334,10 @@ void NativeWidgetWin::SetAlwaysOnTop(bool on_top) {
   message_handler_->SetAlwaysOnTop(on_top);
 }
 
+bool NativeWidgetWin::IsAlwaysOnTop() const {
+  return message_handler_->IsAlwaysOnTop();
+}
+
 void NativeWidgetWin::Maximize() {
   message_handler_->Maximize();
 }