Split Screen mode implementation

athena/wm/public/window_list_provider.h

+// Copyright 2014 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 ATHENA_WM_PUBLIC_WINDOW_LIST_PROVIDER_H_
+#define ATHENA_WM_PUBLIC_WINDOW_LIST_PROVIDER_H_
+
+#include "athena/athena_export.h"
+#include "ui/aura/window.h"
+
+namespace athena {
+
+// Interface for an ordered list of aura::Window objects.
+class ATHENA_EXPORT WindowListProvider {
+ public:
+  virtual ~WindowListProvider() {}
+
+  // Returns an ordered list of windows.
+  virtual aura::Window::Windows GetWindowList() const = 0;
+
+  // Moves the window to the front of the list.
+  virtual void MoveToFront(aura::Window* window) = 0;
+};
+
+}  // namespace athena
+
+#endif  // ATHENA_WM_PUBLIC_WINDOW_LIST_PROVIDER_H_