1 files changed, 31 insertions, 0 deletions
diff --git a/ui/aura/client/activation_change_observer.h b/ui/aura/client/activation_change_observer.h
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+++ b/ui/aura/client/activation_change_observer.h
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+// 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_CLIENT_ACTIVATION_CHANGE_OBSERVER_H_
+#define UI_AURA_CLIENT_ACTIVATION_CHANGE_OBSERVER_H_
+#pragma once
+
+#include "ui/aura/aura_export.h"
+
+namespace aura {
+class Window;
+
+namespace client {
+
+class AURA_EXPORT ActivationChangeObserver {
+ public:
+  // Called when |active| gains focus, or there is no active window
+  // (|active| is NULL in this case.) |old_active| refers to the
+  // previous active window or NULL if there was no previously active
+  // window.
+  virtual void OnWindowActivated(Window* active, Window* old_active) = 0;
+
+ protected:
+  virtual ~ActivationChangeObserver() {}
+};
+
+}  // namespace client
+}  // namespace aura
+
+#endif  // UI_AURA_CLIENT_ACTIVATION_CHANGE_OBSERVER_H_