ash: Add RootWindowHostFactory class.

ash/display/display_manager_delegate.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 ASH_DISPLAY_DISPLAY_MANAGER_DELEGATE_H_
+#define ASH_DISPLAY_DISPLAY_MANAGER_DELEGATE_H_
+
+namespace aura {
+class RootWindowDelegate;
+}
+
+namespace ash {
+namespace internal {
+
+// Delegate of the DisplayManager.
+class DisplayManagerDelegate {
+ public:
+  virtual ~DisplayManagerDelegate() {}
+
+  // Creates a new RootWindowDelegate. DisplayManager takes ownership
+  // of the returned value.
+  virtual aura::RootWindowDelegate* CreateRootWindowDelegate() = 0;
+};
+
+}  // namespace internal
+}  // namespace ash
+
+#endif  // ASH_DISPLAY_DISPLAY_MANAGER_DELEGATE_H_