Adds WmWindow and converts WindowState to use it

ash/wm/aura/wm_root_window_controller_aura.h

Index: ash/wm/aura/wm_root_window_controller_aura.h
diff --git a/ash/wm/aura/wm_root_window_controller_aura.h b/ash/wm/aura/wm_root_window_controller_aura.h
new file mode 100644
index 0000000000000000000000000000000000000000..9b2e95ad0725f1d27e5ab867a81f914b20b20cf6
--- /dev/null
+++ b/ash/wm/aura/wm_root_window_controller_aura.h
@@ -0,0 +1,46 @@
+// Copyright 2016 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 ASH_WM_AURA_WM_ROOT_CONTROLLER_AURA_H_
+#define ASH_WM_AURA_WM_ROOT_CONTROLLER_AURA_H_
+
+#include "ash/ash_export.h"
+#include "ash/wm/common/wm_root_window_controller.h"
+#include "base/macros.h"
+
+namespace aura {
+class Window;
+}
+
+namespace ash {
+
+class RootWindowController;
+
+namespace wm {
+
+class ASH_EXPORT WmRootWindowControllerAura : public WmRootWindowController {
+ public:
+  explicit WmRootWindowControllerAura(
+      RootWindowController* root_window_controller);
+  ~WmRootWindowControllerAura() override;
+
+  static WmRootWindowControllerAura* Get(aura::Window* window) {
+    return const_cast<WmRootWindowControllerAura*>(
+        Get(const_cast<const aura::Window*>(window)));
+  }
+  static const WmRootWindowControllerAura* Get(const aura::Window* window);
+
+  // WmRootWindowController:
+  bool HasShelf() override;
+
+ private:
+  RootWindowController* root_window_controller_;
+
+  DISALLOW_COPY_AND_ASSIGN(WmRootWindowControllerAura);
+};
+
+}  // namespace wm
+}  // namespace ash
+
+#endif  // ASH_WM_AURA_WM_ROOT_CONTROLLER_AURA_H_