Rework ash::CursorManager into a corewm object, to share code with desktop.

ui/views/widget/desktop_aura/desktop_root_window_host_linux.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_linux.h"
 
 #include <X11/extensions/XInput2.h>
 #include <X11/Xatom.h>
 #include <X11/Xutil.h>
 
@@ skipping 768 matching lines @@
 bool DesktopRootWindowHostLinux::ConfineCursorToRootWindow() {
   NOTIMPLEMENTED();
   return false;
 }
 
 void DesktopRootWindowHostLinux::UnConfineCursor() {
   NOTIMPLEMENTED();
 }
 
 void DesktopRootWindowHostLinux::OnCursorVisibilityChanged(bool show) {
-  NOTIMPLEMENTED();
 }
 
 void DesktopRootWindowHostLinux::MoveCursorTo(const gfx::Point& location) {
   NOTIMPLEMENTED();
 }
 
 void DesktopRootWindowHostLinux::SetFocusWhenShown(bool focus_when_shown) {
   static const char* k_NET_WM_USER_TIME = "_NET_WM_USER_TIME";
   focus_when_shown_ = focus_when_shown;
   if (IsWindowManagerPresent() && !focus_when_shown_) {
@@ skipping 296 matching lines @@
 DesktopRootWindowHost* DesktopRootWindowHost::Create(
     internal::NativeWidgetDelegate* native_widget_delegate,
     DesktopNativeWidgetAura* desktop_native_widget_aura,
     const gfx::Rect& initial_bounds) {
   return new DesktopRootWindowHostLinux(native_widget_delegate,
                                         desktop_native_widget_aura,
                                         initial_bounds);
 }
 
 }  // namespace views