Set the unique_event_id when converting from TouchEvent to WebTouchEvent

ui/events/event.h

Index: ui/events/event.h
diff --git a/ui/events/event.h b/ui/events/event.h
index b65c27516ab48f1f6d4e4f1b00a2270524cd2a9a..a7c20906dcec253e5e96479b0b4bde25612e9cfe 100644
--- a/ui/events/event.h
+++ b/ui/events/event.h
@@ -492,7 +492,7 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
   TouchEvent(const TouchEvent& model, T* source, T* target)
       : LocatedEvent(model, source, target),
         touch_id_(model.touch_id_),
-        unique_event_id_(model.unique_event_id_),
+        unique_touch_event_id_(model.unique_touch_event_id_),
         radius_x_(model.radius_x_),
         radius_y_(model.radius_y_),
         rotation_angle_(model.rotation_angle_),
@@ -520,7 +520,7 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
   // The id of the pointer this event modifies.
   int touch_id() const { return touch_id_; }
   // A unique identifier for this event.
-  uint64 unique_event_id() const { return unique_event_id_; }
+  uint32 unique_touch_event_id() const { return unique_touch_event_id_; }
   // If we aren't provided with a radius on one axis, use the
   // information from the other axis.
   float radius_x() const { return radius_x_ > 0 ? radius_x_ : radius_y_; }
@@ -560,7 +560,7 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
   const int touch_id_;
 
   // A unique identifier for the touch event.
-  const uint64 unique_event_id_;
+  const uint32 unique_touch_event_id_;
 
   // Radius of the X (major) axis of the touch ellipse. 0.0 if unknown.
   float radius_x_;