Gestures are now possible using touch events with any ids

ui/aura/gestures/gesture_point.cc

 // Copyright (c) 2012 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/aura/gestures/gesture_point.h"
 
 #include <cmath>
 
 #include "base/basictypes.h"
 #include "ui/aura/event.h"
 #include "ui/aura/gestures/gesture_configuration.h"
 #include "ui/base/events.h"
 
 namespace {
 
 const int kMinRailBreakVelocity = 200;
 const int kMinScrollDeltaSquared = 5 * 5;
 const int kRailBreakProportion = 15;
 const int kRailStartProportion = 2;
 const int kBufferedPoints = 10;
 
 }  // namespace
 
 namespace aura {
 
 GesturePoint::GesturePoint()
     : first_touch_time_(0.0),
       last_touch_time_(0.0),
       last_tap_time_(0.0),
-      velocity_calculator_(kBufferedPoints) {
+      velocity_calculator_(kBufferedPoints),
+      point_id_(-1) {
 }
 
 GesturePoint::~GesturePoint() {}
 
 void GesturePoint::Reset() {
   first_touch_time_ = last_touch_time_ = 0.0;
   velocity_calculator_.ClearHistory();
+  point_id_ = -1;
 }
 
 void GesturePoint::UpdateValues(const TouchEvent& event) {
   const int64 event_timestamp_microseconds =
       event.time_stamp().InMicroseconds();
   if (event.type() == ui::ET_TOUCH_MOVED) {
     velocity_calculator_.PointSeen(event.x(),
                                    event.y(),
                                    event_timestamp_microseconds);
   }
@@ skipping 114 matching lines @@
   return manhattanDistance <
       GestureConfiguration::max_touch_move_in_pixels_for_click();
 }
 
 bool GesturePoint::IsOverMinFlickSpeed() {
   return velocity_calculator_.VelocitySquared() >
       GestureConfiguration::min_flick_speed_squared();
 }
 
 }  // namespace aura