Remove --show-app-list-shortcut flag and implement new app launcher enable logic.

apps/switches.cc

Index: apps/switches.cc
diff --git a/apps/switches.cc b/apps/switches.cc
deleted file mode 100644
index f5051c9aa5fe616703ce1d4fc9c588d6fd14a573..0000000000000000000000000000000000000000
--- a/apps/switches.cc
+++ /dev/null
@@ -1,14 +0,0 @@
-// 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.
-
-#include "apps/switches.h"
-
-namespace apps {
-namespace switches {
-
-// If true an app list shortcut will be shown in the taskbar.
-const char kShowAppListShortcut[] = "show-app-list-shortcut";
-
-}  // namespace switches
-}  // namespace apps