Add the supporting code for the cast system tray integration

ash/cast_config_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/cast_config_delegate.h"
+
+namespace ash {
+
+CastConfigDelegate::Receiver::Receiver() {
+}
+
+CastConfigDelegate::Receiver::~Receiver() {
+}
+
+CastConfigDelegate::Activity::Activity() {
+}
+
+CastConfigDelegate::Activity::~Activity() {
+}
+
+CastConfigDelegate::ReceiverAndActivity::ReceiverAndActivity() {
+}
+
+CastConfigDelegate::ReceiverAndActivity::~ReceiverAndActivity() {
+}
+
+}  // namespace ash