ozone: Map TouchEvent::touch_id_ into expected range

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 72 matching lines @@
     base::FilePath path,
     int id,
     InputDeviceType type,
     DeviceEventDispatcherEvdev* dispatcher)
     : EventConverterEvdev(fd, path, id, type),
       dispatcher_(dispatcher),
       syn_dropped_(false),
       has_mt_(false),
       touch_points_(0),
       next_tracking_id_(0),
-      current_slot_(0) {
+      current_slot_(0),
+      touch_id_offset_(0) {
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kExtraTouchNoiseFiltering)) {
     touch_noise_finder_.reset(new TouchNoiseFinder);
   }
 }
 
 TouchEventConverterEvdev::~TouchEventConverterEvdev() {
   Stop();
   close(fd_);
 }
@@ skipping 87 matching lines @@
 }
 
 gfx::Size TouchEventConverterEvdev::GetTouchscreenSize() const {
   return gfx::Size(x_num_tuxels_, y_num_tuxels_);
 }
 
 int TouchEventConverterEvdev::GetTouchPoints() const {
   return touch_points_;
 }
 
+void TouchEventConverterEvdev::SetTouchIdOffset(int offset) {
+  touch_id_offset_ = offset;
+}
+
 void TouchEventConverterEvdev::OnFileCanReadWithoutBlocking(int fd) {
   input_event inputs[kNumTouchEvdevSlots * 6 + 1];
   ssize_t read_size = read(fd, inputs, sizeof(inputs));
   if (read_size < 0) {
     if (errno == EINTR || errno == EAGAIN)
       return;
     if (errno != ENODEV)
       PLOG(ERROR) << "error reading device " << path_.value();
     Stop();
     return;
@@ skipping 139 matching lines @@
   }
 
   if (touch.touching)
     return touch.was_touching ? ET_TOUCH_MOVED : ET_TOUCH_PRESSED;
   return touch.was_touching ? ET_TOUCH_RELEASED : ET_UNKNOWN;
 }
 
 void TouchEventConverterEvdev::ReportEvent(const InProgressTouchEvdev& event,
                                            EventType event_type,
                                            const base::TimeDelta& timestamp) {
-  dispatcher_->DispatchTouchEvent(TouchEventParams(
-      id_, event.slot, event_type, gfx::PointF(event.x, event.y),
-      gfx::Vector2dF(event.radius_x, event.radius_y), event.pressure,
-      timestamp));
+  dispatcher_->DispatchTouchEvent(
+      TouchEventParams(id_, touch_id_offset_ + event.slot, event_type,
+                       gfx::PointF(event.x, event.y),
+                       gfx::Vector2dF(event.radius_x, event.radius_y),
+                       event.pressure, timestamp));
 }
 
 void TouchEventConverterEvdev::ReportEvents(base::TimeDelta delta) {
   if (touch_noise_finder_)
     touch_noise_finder_->HandleTouches(events_, delta);
 
   for (size_t i = 0; i < events_.size(); i++) {
     InProgressTouchEvdev* event = &events_[i];
     if (!event->altered)
       continue;
@@ skipping 15 matching lines @@
   if (pressure_max_ - pressure_min_)
     pressure /= pressure_max_ - pressure_min_;
   return pressure;
 }
 
 int TouchEventConverterEvdev::NextTrackingId() {
   return next_tracking_id_++ & kMaxTrackingId;
 }
 
 }  // namespace ui