Wires up transient windows for aura-mus

ui/wm/public/transient_window_client.cc

Index: ui/wm/public/transient_window_client.cc
diff --git a/ui/wm/public/transient_window_client.cc b/ui/wm/public/transient_window_client.cc
deleted file mode 100644
index 6397e6690a415a320f698f188d57888078fd359b..0000000000000000000000000000000000000000
--- a/ui/wm/public/transient_window_client.cc
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright 2014 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 "ui/wm/public/transient_window_client.h"
-
-namespace aura {
-namespace client {
-
-namespace {
-
-TransientWindowClient* instance = nullptr;
-
-}  // namespace
-
-void SetTransientWindowClient(TransientWindowClient* client) {
-  instance = client;
-}
-
-TransientWindowClient* GetTransientWindowClient() {
-  return instance;
-}
-
-}  // namespace client
-}  // namespace aura