Adds views::corewm::WMState to install common state

ui/views/corewm/wm_state.h

Index: ui/views/corewm/wm_state.h
diff --git a/ui/views/corewm/wm_state.h b/ui/views/corewm/wm_state.h
new file mode 100644
index 0000000000000000000000000000000000000000..1e0ee4f5b604f1eac7f47860398ca65a132f9ced
--- /dev/null
+++ b/ui/views/corewm/wm_state.h
@@ -0,0 +1,32 @@
+// 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.
+
+#ifndef UI_VIEWS_COREWM_WM_STATE_H_
+#define UI_VIEWS_COREWM_WM_STATE_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "ui/views/views_export.h"
+
+namespace views {
+namespace corewm {
+
+class TransientWindowStackingClient;
+
+// Installs state needed by the window manager.
+class VIEWS_EXPORT WMState {
+ public:
+  WMState();
+  ~WMState();
+
+  // WindowStackingClient:
+ private:
+  scoped_ptr<TransientWindowStackingClient> window_stacking_client_;
+
+  DISALLOW_COPY_AND_ASSIGN(WMState);
+};
+
+}  // namespace corewm
+}  // namespace views
+
+#endif  // UI_VIEWS_COREWM_WM_STATE_H_