Extract touchscreen device management into a generic manager

ui/events/device_data_manager.h

Index: ui/events/device_data_manager.h
diff --git a/ui/events/device_data_manager.h b/ui/events/device_data_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..7cfa87e45a9b5d99f8232a1666c31ba6d59b6ee9
--- /dev/null
+++ b/ui/events/device_data_manager.h
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+// 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 UI_EVENTS_DEVICE_DATA_MANAGER_H_
+#define UI_EVENTS_DEVICE_DATA_MANAGER_H_
+
+#include <stdint.h>
+
+#include "base/macros.h"
+#include "ui/events/events_base_export.h"
+#include "ui/gfx/transform.h"
+
+template <typename T> struct DefaultSingletonTraits;
+
+namespace ui {
+
+// Keeps track of device mappings and event transformations.
+class EVENTS_BASE_EXPORT DeviceDataManager {
+ public:
+  static DeviceDataManager* GetInstance();
+
+  void ClearTouchTransformerRecord();
+  void UpdateTouchInfoForDisplay(int64_t display_id,
+                                 int touch_device_id,
+                                 const gfx::Transform& touch_transformer);
+  void ApplyTouchTransformer(int touch_device_id, float* x, float* y);
+  int64_t GetDisplayForTouchDevice(int touch_device_id) const;
+
+ protected:
+  // Requirement for Singleton.
+  friend struct DefaultSingletonTraits<DeviceDataManager>;
+
+  DeviceDataManager();
+  virtual ~DeviceDataManager();
+
+  bool IsTouchDeviceIdValid(int touch_device_id) const;
+
+  static const int kMaxDeviceNum = 128;
+
+  // Table to keep track of which display id is mapped to which touch device.
+  int64_t touch_device_to_display_map_[kMaxDeviceNum];
+  // Index table to find the TouchTransformer for a touch device.
+  gfx::Transform touch_device_transformer_map_[kMaxDeviceNum];
+
+  DISALLOW_COPY_AND_ASSIGN(DeviceDataManager);
+};
+
+}  // namespace ui
+
+#endif  // UI_EVENTS_DEVICE_DATA_MANAGER_H_