Added experimental Touch.tilt, Touch.tiltDirection support for Android

ui/events/event.h

Index: ui/events/event.h
diff --git a/ui/events/event.h b/ui/events/event.h
index e32e77c6700ca50b35a6224b07774cd763be9661..da110dce201cd00c67120f508ee6632efa524624 100644
--- a/ui/events/event.h
+++ b/ui/events/event.h
@@ -495,6 +495,8 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
         radius_y_(model.radius_y_),
         rotation_angle_(model.rotation_angle_),
         force_(model.force_),
+        tilt_(model.tilt_),
+        tiltDirection_(model.tiltDirection_),
         may_cause_scrolling_(model.may_cause_scrolling_) {}
 
   TouchEvent(EventType type,
@@ -510,7 +512,9 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
              float radius_x,
              float radius_y,
              float angle,
-             float force);
+             float force,
+             float tilt,
+             float tiltDirection);
 
   ~TouchEvent() override;
 
@@ -524,6 +528,8 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
   float radius_y() const { return radius_y_ > 0 ? radius_y_ : radius_x_; }
   float rotation_angle() const { return rotation_angle_; }
   float force() const { return force_; }
+  float tilt() const { return tilt_; }
+  float tiltDirection() const { return tiltDirection_; }
 
   void set_may_cause_scrolling(bool causes) { may_cause_scrolling_ = causes; }
   bool may_cause_scrolling() const { return may_cause_scrolling_; }
@@ -566,6 +572,14 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
   // Force (pressure) of the touch. Normalized to be [0, 1]. Default to be 0.0.
   float force_;
 
+  // Tilt angle of the stylus away from the perpendicular to the screen.
+  // Default is NaN.
+  float tilt_;
+
+  // Clockwise angle from the X axis to the XY-projection of the stylus.
+  // Range is [-180, 180), default is NaN.
+  float tiltDirection_;
+
   // Whether the (unhandled) touch event will produce a scroll event (e.g., a
   // touchmove that exceeds the platform slop region, or a touchend that
   // causes a fling). Defaults to false.