Moving input device hotplug event processing outside of ui/display

ash/touch/touchscreen_util.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 ASH_TOUCH_TOUCHSCREEN_UTIL_H_
+#define ASH_TOUCH_TOUCHSCREEN_UTIL_H_
+
+#include <vector>
+
+#include "ash/ash_export.h"
+#include "ash/display/display_info.h"
+#include "ui/events/touchscreen_device.h"
+
+namespace ash {
+
+// Given a list of displays and a list of touchscreens, associate them. The
+// information in |displays| will be updated to reflect the mapping.
+ASH_EXPORT void AssociateTouchscreens(
+    std::vector<DisplayInfo>* displays,
+    const std::vector<ui::TouchscreenDevice>& touchscreens);
+
+}  // namespace ash
+
+#endif  // ASH_TOUCH_TOUCHSCREEN_UTIL_H_