apps: Stop depending on chrome_switches.h

apps/switches.cc

 // Copyright 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.
 
-#ifndef APPS_PREF_NAMES_H_
-#define APPS_PREF_NAMES_H_
+#include "apps/switches.h"
 
 namespace apps {
+namespace switches {
 
-namespace prefs {
+// If true an app list shortcut will be shown in the taskbar.
+const char kShowAppListShortcut[] = "show-app-list-shortcut";
 
-extern const char kAppLauncherIsEnabled[];
-
-}  // namespace prefs
-
+}  // namespace switches
 }  // namespace apps
-
-#endif  // APPS_PREF_NAMES_H_