mus: Remove the old client lib.

services/ui/public/cpp/window_tree_client_delegate.cc

Index: services/ui/public/cpp/window_tree_client_delegate.cc
diff --git a/services/ui/public/cpp/window_tree_client_delegate.cc b/services/ui/public/cpp/window_tree_client_delegate.cc
deleted file mode 100644
index 7e3703a867181011721a4eb768f650cf7feabc8b..0000000000000000000000000000000000000000
--- a/services/ui/public/cpp/window_tree_client_delegate.cc
+++ /dev/null
@@ -1,11 +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 "services/ui/public/cpp/window_tree_client_delegate.h"
-
-namespace ui {
-
-void WindowTreeClientDelegate::OnUnembed(Window* root) {}
-
-}  // namespace ui