aura-x11: Fix touch-calibration for multi-monitor setups.

ui/base/events/event.h

Index: ui/base/events/event.h
diff --git a/ui/base/events/event.h b/ui/base/events/event.h
index d2cec15ef9dc1e68c3f13006f9537db92a8f962e..ba93d3b5492a541af13ca0c3742ad9b84e23affd 100644
--- a/ui/base/events/event.h
+++ b/ui/base/events/event.h
@@ -402,6 +402,12 @@ class UI_EXPORT TouchEvent : public LocatedEvent {
   float rotation_angle() const { return rotation_angle_; }
   float force() const { return force_; }
 
+  // Calibrate the touch-point. This is useful when the touch-surface that
+  // generates the events need to be remapped to a surface of a different
+  // size. |from| is the size of the native surface, and |to| is the size
+  // of the target surface.
+  void CalibrateLocation(const gfx::Size& from, const gfx::Size& to);
+
   // Used for unit tests.
   void set_radius_x(const float r) { radius_x_ = r; }
   void set_radius_y(const float r) { radius_y_ = r; }