[WIP][Ozone] Support external touchscreens

ui/ozone/platform/dri/touch_converter.h

Index: ui/ozone/platform/dri/touch_converter.h
diff --git a/ui/ozone/platform/dri/touch_converter.h b/ui/ozone/platform/dri/touch_converter.h
new file mode 100644
index 0000000000000000000000000000000000000000..d08dc950a8c82526ad3df3b0e4ff1da1791ca221
--- /dev/null
+++ b/ui/ozone/platform/dri/touch_converter.h
@@ -0,0 +1,66 @@
+// 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_OZONE_PLATFORM_DRI_TOUCH_CONVERTER_H_
+#define UI_OZONE_PLATFORM_DRI_TOUCH_CONVERTER_H_
+
+#include "base/macros.h"
+#include "ui/gfx/transform.h"
+
+namespace ui {
+
+class DisplayManager;
+class DriWindow;
+class TouchEvent;
+
+// Translates a touch event from the touchscreen coordinate system to the
+// window coordinate system.
+class TouchConverter {
+ public:
+  explicit TouchConverter(DriWindow* window, DisplayManager* display_manager);
+  ~TouchConverter();
+
+  // Returns true if the touch event is associated with |window_|. False
+  // otherwise.
+  bool CanHandleEvent(const TouchEvent& event);
+
+  // Update the event properties such that the event is reported in the
+  // window's coordinate system.
+  void RewriteTouchEvent(TouchEvent* event);
+
+  // Force updating the event transformation matrix.
+  void UpdateTransform();
+
+ private:
+  void GetTouchCalibration();
+
+  struct TouchCalibration {
+    TouchCalibration()
+        : bezel_left(0), bezel_right(0), bezel_top(0), bezel_bottom(0) {}
+
+    int bezel_left;
+    int bezel_right;
+    int bezel_top;
+    int bezel_bottom;
+  };
+
+  DriWindow* window_;                // Not owned.
+  DisplayManager* display_manager_;  // Not owned.
+
+  // Keep track of the touchscreen area that isn't directly on top of the
+  // display.
+  TouchCalibration touch_calibration_;
+
+  int64_t cached_touchscreen_id_;
+
+  gfx::Transform transform_;
+
+  float scale_factor_;
+
+  DISALLOW_COPY_AND_ASSIGN(TouchConverter);
+};
+
+}  // namespace ui
+
+#endif  // UI_OZONE_PLATFORM_DRI_TOUCH_CONVERTER_H_