Add ash::VPNDelegate and Chrome OS implementation

ash/system/chromeos/network/vpn_delegate.cc

+// Copyright 2015 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/system/chromeos/network/vpn_delegate.h"
+
+namespace ash {
+
+VPNProvider::VPNProvider(const std::string& name, const std::string& id)
+    : name(name), id(id) {
+}
+
+VPNProvider::~VPNProvider() {
+}
+
+VPNDelegate::Observer::~Observer() {
+}
+
+VPNDelegate::VPNDelegate() {
+}
+
+VPNDelegate::~VPNDelegate() {
+}
+
+void VPNDelegate::AddObserver(Observer* observer) {
+  observer_list_.AddObserver(observer);
+}
+
+void VPNDelegate::RemoveObserver(Observer* observer) {
+  observer_list_.RemoveObserver(observer);
+}
+
+void VPNDelegate::NotifyObservers() {
+  FOR_EACH_OBSERVER(Observer, observer_list_,
+                    OnThirdPartyVPNProvidersChanged());
+}
+
+}  // namespace ash