Reland: chromeos: Convert ash VPNDelegate interface to mojo

ash/mus/vpn_delegate_mus.cc

Index: ash/mus/vpn_delegate_mus.cc
diff --git a/ash/mus/vpn_delegate_mus.cc b/ash/mus/vpn_delegate_mus.cc
deleted file mode 100644
index 8e8a76708141ecdc9852f618ba5f5734dacceedd..0000000000000000000000000000000000000000
--- a/ash/mus/vpn_delegate_mus.cc
+++ /dev/null
@@ -1,17 +0,0 @@
-// 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 "ash/mus/vpn_delegate_mus.h"
-
-namespace ash {
-
-VPNDelegateMus::VPNDelegateMus() {}
-
-VPNDelegateMus::~VPNDelegateMus() {}
-
-void VPNDelegateMus::ShowAddPage(const std::string& extension_id) {
-  // TODO(mash): http://crbug.com/651148
-}
-
-}  // namespace ash