Add ui devtools server

ui/devtools/switches.cc

Index: ui/devtools/switches.cc
diff --git a/ui/devtools/switches.cc b/ui/devtools/switches.cc
new file mode 100644
index 0000000000000000000000000000000000000000..df15a908080d3c37fc3c55ed4a75cfb5f4b138fe
--- /dev/null
+++ b/ui/devtools/switches.cc
@@ -0,0 +1,15 @@
+// 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 "ui/devtools/switches.h"
+
+namespace ui {
+namespace devtools {
+
+// Enables DevTools server for UI (mus, ash, etc). Value should be the port the
+// server is started on. Default port is 9332.
+const char kEnableUiDevTools[] = "enable-ui-devtools";
+
+}  // namespace devtools
+}  // namespace ui