exo: Implement support for zcr_keyboard_configuration_v1 protocol.

components/exo/keyboard_device_configuration_delegate.h

+// 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 COMPONENTS_EXO_KEYBOARD_DEVICE_CONFIGURATION_H_
+#define COMPONENTS_EXO_KEYBOARD_DEVICE_CONFIGURATION_H_
+
+namespace exo {
+class Keyboard;
+
+// Used as an extension to the KeyboardDelegate.
+class KeyboardDeviceConfigurationDelegate {
+ public:
+  // Called at the top of the keyboard's destructor, to give observers a chance
+  // to remove themselves.
+  virtual void OnKeyboardDestroying(Keyboard* keyboard) = 0;
+
+  // Called when used keyboard type changed.
+  virtual void OnKeyboardTypeChanged(bool is_physical) = 0;
+
+ protected:
+  virtual ~KeyboardDeviceConfigurationDelegate() {}
+};
+
+}  // namespace exo
+
+#endif  // COMPONENTS_EXO_KEYBOARD_DEVICE_CONFIGURATION_H_