Pass MotionEvent tilt angles to Blink on Android.

ui/events/gesture_detection/motion_event_generic.h

Index: ui/events/gesture_detection/motion_event_generic.h
diff --git a/ui/events/gesture_detection/motion_event_generic.h b/ui/events/gesture_detection/motion_event_generic.h
index 2a9a606b44d3c66057f40ae44ee1c590c69f4f44..71dc92b7557a1c4bb6d5e86db7d9251c4098775a 100644
--- a/ui/events/gesture_detection/motion_event_generic.h
+++ b/ui/events/gesture_detection/motion_event_generic.h
@@ -34,6 +34,7 @@ struct GESTURE_DETECTION_EXPORT PointerProperties {
   float touch_major;
   float touch_minor;
   float orientation;
+  float tilt;
   // source_device_id is only used on Aura.
   int source_device_id;
 };
@@ -62,6 +63,7 @@ class GESTURE_DETECTION_EXPORT MotionEventGeneric : public MotionEvent {
   float GetTouchMinor(size_t pointer_index) const override;
   float GetOrientation(size_t pointer_index) const override;
   float GetPressure(size_t pointer_index) const override;
+  float GetTilt(size_t pointer_index) const override;
   ToolType GetToolType(size_t pointer_index) const override;
   int GetButtonState() const override;
   int GetFlags() const override;