app_list: Create an app_list_switches.* to put all app list switches.

ui/app_list/app_list_switches.cc

Index: ui/app_list/app_list_switches.cc
diff --git a/ui/app_list/app_list_switches.cc b/ui/app_list/app_list_switches.cc
new file mode 100644
index 0000000000000000000000000000000000000000..2c993747bc0cfae6c5730091471384e8289c05d1
--- /dev/null
+++ b/ui/app_list/app_list_switches.cc
@@ -0,0 +1,14 @@
+// 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/app_list/app_list_switches.h"
+
+namespace app_list {
+namespace switches {
+
+// Show only apps result in app list search.
+const char kAppListShowAppsOnly[] = "app-list-show-apps-only";
+
+}  // namespace switches
+}  // namespace app_list