Revert "ozone: evdev: Use tracking id for TouchEvent finger id"

ui/events/ozone/evdev/touch_event_converter_evdev.cc

 // 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.
 
 #include "ui/events/ozone/evdev/touch_event_converter_evdev.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <linux/input.h>
 #include <poll.h>
@@ skipping 274 matching lines @@
   }
 }
 
 void TouchEventConverterEvdev::ReportEvents(base::TimeDelta delta) {
   for (int i = 0; i < MAX_FINGERS; i++) {
     if (altered_slots_[i]) {
       // TODO(rikroege): Support elliptical finger regions.
       TouchEvent evt(events_[i].type_,
                      gfx::PointF(events_[i].x_, events_[i].y_),
                      /* flags */ 0,
-                     /* touch_id */ events_[i].finger_,
+                     /* touch_id */ i,
                      delta,
                      /* radius_x */ events_[i].radius_x_,
                      /* radius_y */ events_[i].radius_y_,
                      /* angle */ 0.,
                      events_[i].pressure_);
       DispatchEventToCallback(&evt);
 
       // Subsequent events for this finger will be touch-move until it
       // is released.
       events_[i].type_ = ET_TOUCH_MOVED;
     }
   }
   altered_slots_.reset();
 }
 
 }  // namespace ui