Stack at top functionality for Aura-based windows

ui/views/widget/desktop_aura/desktop_root_window_host_x11.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/views/widget/desktop_aura/desktop_root_window_host_x11.h"
 
 #include <X11/extensions/shape.h>
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
 #include <X11/Xregion.h>
@@ skipping 334 matching lines @@
 
 bool DesktopRootWindowHostX11::IsVisible() const {
   return window_mapped_;
 }
 
 void DesktopRootWindowHostX11::SetSize(const gfx::Size& size) {
   // TODO(erg):
   NOTIMPLEMENTED();
 }
 
+void DesktopRootWindowHostX11::StackAtTop() {
+  XRaiseWindow(xdisplay_, xwindow_);
+}
+
 void DesktopRootWindowHostX11::CenterWindow(const gfx::Size& size) {
   gfx::Rect parent_bounds = GetWorkAreaBoundsInScreen();
 
   // If |window_|'s transient parent bounds are big enough to contain |size|,
   // use them instead.
   if (content_window_->transient_parent()) {
     gfx::Rect transient_parent_rect =
         content_window_->transient_parent()->GetBoundsInScreen();
     if (transient_parent_rect.height() >= size.height() &&
         transient_parent_rect.width() >= size.width()) {
@@ skipping 1156 matching lines @@
   if (linux_ui) {
     ui::NativeTheme* native_theme = linux_ui->GetNativeTheme();
     if (native_theme)
       return native_theme;
   }
 
   return ui::NativeTheme::instance();
 }
 
 }  // namespace views