Moves management of transients out of Window

ui/views/corewm/wm_state.cc

 // Copyright (c) 2013 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/views/corewm/wm_state.h"
 
+#include "ui/views/corewm/transient_window_controller.h"
 #include "ui/views/corewm/transient_window_stacking_client.h"
 
 namespace views {
 namespace corewm {
 
 WMState::WMState()
-    : window_stacking_client_(new TransientWindowStackingClient) {
+    : window_stacking_client_(new TransientWindowStackingClient),
+      transient_window_client_(new TransientWindowController) {
   aura::client::SetWindowStackingClient(window_stacking_client_.get());
+  aura::client::SetTransientWindowClient(transient_window_client_.get());
 }
 
 WMState::~WMState() {
   if (aura::client::GetWindowStackingClient() == window_stacking_client_.get())
     aura::client::SetWindowStackingClient(NULL);
+
+  if (aura::client::GetTransientWindowClient() ==
+      transient_window_client_.get()) {
+    aura::client::SetTransientWindowClient(NULL);
+  }
 }
 
 }  // namespace corewm
 }  // namespace views