cros: Remove some OS platform ifdefs from ash

ash/mus/bridge/wm_shell_mus.cc

 // Copyright 2016 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 "ash/mus/bridge/wm_shell_mus.h"
 
 #include <utility>
 
 #include "ash/common/accelerators/accelerator_controller.h"
 #include "ash/common/key_event_watcher.h"
@@ skipping 405 matching lines @@
 void WmShellMus::RequestShutdown() {
   NOTIMPLEMENTED();
 }
 
 bool WmShellMus::IsTouchDown() {
   // TODO: implement me, http://crbug.com/634967.
   // NOTIMPLEMENTED is too spammy here.
   return false;
 }
 
-#if defined(OS_CHROMEOS)
 void WmShellMus::ToggleIgnoreExternalKeyboard() {
   NOTIMPLEMENTED();
 }
 
 void WmShellMus::SetLaserPointerEnabled(bool enabled) {
   NOTIMPLEMENTED();
 }
-#endif  // defined(OS_CHROMEOS)
 
 // TODO: support OnAttemptToReactivateWindow, http://crbug.com/615114.
 // TODO: Nuke and let client code use ActivationChangeObserver directly.
 void WmShellMus::OnWindowActivated(ActivationReason reason,
                                    aura::Window* gained_active,
                                    aura::Window* lost_active) {
   WmWindow* gained_active_wm = WmWindowMus::Get(gained_active);
   if (gained_active_wm)
     set_root_window_for_new_windows(gained_active_wm->GetRootWindow());
   WmWindow* lost_active_wm = WmWindowMus::Get(lost_active);
   for (auto& observer : activation_observers_)
     observer.OnWindowActivated(gained_active_wm, lost_active_wm);
 }
 
 }  // namespace mus
 }  // namespace ash