Remove ash_util namespace

chrome/browser/fullscreen_chromeos.cc

 // Copyright (c) 2013 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 "chrome/browser/fullscreen.h"
 
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "chrome/browser/ui/ash/ash_util.h"
 #include "ui/display/display.h"
 #include "ui/display/screen.h"
 
 bool IsFullScreenMode(int64_t display_id) {
-  if (ash_util::IsRunningInMash()) {
+  if (IsRunningInMash()) {
     // TODO: http://crbug.com/640390.
     NOTIMPLEMENTED();
     return false;
   }
 
   for (ash::RootWindowController* controller :
        ash::Shell::GetInstance()->GetAllRootWindowControllers()) {
     if (display::Screen::GetScreen()
             ->GetDisplayNearestWindow(controller->GetRootWindow())
             .id() == display_id) {
       return controller && controller->GetWindowForFullscreenMode();
     }
   }
 
   return false;
 }