Remove Chromecast extension support from cast system tray menu.

ash/common/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/common/cast_config_delegate.h"
 
 namespace ash {
 
-CastConfigDelegate::Receiver::Receiver() {}
+CastConfigDelegate::Sink::Sink() {}
 
-CastConfigDelegate::Receiver::~Receiver() {}
+CastConfigDelegate::Sink::~Sink() {}
 
-CastConfigDelegate::Activity::Activity() {}
+CastConfigDelegate::Route::Route() {}
 
-CastConfigDelegate::Activity::~Activity() {}
+CastConfigDelegate::Route::~Route() {}
 
-CastConfigDelegate::ReceiverAndActivity::ReceiverAndActivity() {}
+CastConfigDelegate::SinkAndRoute::SinkAndRoute() {}
 
-CastConfigDelegate::ReceiverAndActivity::~ReceiverAndActivity() {}
+CastConfigDelegate::SinkAndRoute::~SinkAndRoute() {}
 
 }  // namespace ash