Initial cut at layerless windows.

ui/aura/window_layer_type.h

+// Copyright (c) 2012 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_AURA_WINDOW_LAYER_TYPE_H_
+#define UI_AURA_WINDOW_LAYER_TYPE_H_
+
+namespace aura {
+
+// These constants mirror that of ui::LayerType with the addition of
+// WINDOW_LAYER_NONE. See ui::LayerType for description of ones in common.
+enum WindowLayerType {
+  // Note that Windows with WINDOW_LAYER_NONE impose limitations on the
+  // Window: transforms and animations aren't supported.
+  WINDOW_LAYER_NONE,
+
+  WINDOW_LAYER_NOT_DRAWN,
+  WINDOW_LAYER_TEXTURED,
+  WINDOW_LAYER_SOLID_COLOR,
+};
+
+}  // namespace aura
+
+#endif  // UI_AURA_WINDOW_LAYER_TYPE_H_