Revert 258077 "Remove PrepareForShutdown"

trunk/src/ui/aura/window_tree_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/aura/window_tree_host_x11.h"
 
 #include <strings.h>
 #include <X11/cursorfont.h>
 #include <X11/extensions/Xfixes.h>
 #include <X11/extensions/XInput2.h>
@@ skipping 681 matching lines @@
     default:
       break;
   }
   XSendEvent(xdisplay_, xwindow_, False, 0, &xevent);
 }
 
 void WindowTreeHostX11::OnDeviceScaleFactorChanged(
     float device_scale_factor) {
 }
 
+void WindowTreeHostX11::PrepareForShutdown() {
+  base::MessagePumpX11::Current()->RemoveDispatcherForWindow(xwindow_);
+}
+
 void WindowTreeHostX11::SetCursorNative(gfx::NativeCursor cursor) {
   if (cursor == current_cursor_)
     return;
   current_cursor_ = cursor;
   SetCursorInternal(cursor);
 }
 
 void WindowTreeHostX11::MoveCursorToNative(const gfx::Point& location) {
   XWarpPointer(xdisplay_, None, x_root_window_, 0, 0, 0, 0,
                bounds_.x() + location.x(),
@@ skipping 201 matching lines @@
 }
 
 namespace test {
 
 void SetUseOverrideRedirectWindowByDefault(bool override_redirect) {
   default_override_redirect = override_redirect;
 }
 
 }  // namespace test
 }  // namespace aura