mash: Move system tray cast code into //ash/common

ash/cast_config_delegate.cc

Index: ash/cast_config_delegate.cc
diff --git a/ash/cast_config_delegate.cc b/ash/cast_config_delegate.cc
deleted file mode 100644
index fc0cc3d86153fe54dd1159b15f540539e89e27d6..0000000000000000000000000000000000000000
--- a/ash/cast_config_delegate.cc
+++ /dev/null
@@ -1,21 +0,0 @@
-// 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