ozone: Map TouchEvent::touch_id_ into expected range

ui/events/ozone/evdev/input_device_factory_evdev.cc

 // Copyright 2015 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/input_device_factory_evdev.h"
 
 #include <fcntl.h>
 #include <linux/input.h>
 
 #include "base/stl_util.h"
@@ skipping 173 matching lines @@
 #if defined(USE_EVDEV_GESTURES)
       gesture_property_provider_(new GesturePropertyProvider),
 #endif
       dispatcher_(dispatcher.Pass()),
       pending_device_changes_(0),
       touchscreen_list_dirty_(false),
       keyboard_list_dirty_(false),
       mouse_list_dirty_(false),
       touchpad_list_dirty_(false),
       caps_lock_led_enabled_(false),
+      next_touch_id_offset_(0),
       weak_ptr_factory_(this) {
 }
 
 InputDeviceFactoryEvdev::~InputDeviceFactoryEvdev() {
   STLDeleteValues(&converters_);
 }
 
 void InputDeviceFactoryEvdev::AddInputDevice(int id,
                                              const base::FilePath& path) {
   scoped_ptr<OpenInputDeviceParams> params(new OpenInputDeviceParams);
@@ skipping 34 matching lines @@
     // If we have an existing device, detach it. We don't want two
     // devices with the same name open at the same time.
     if (converters_[path])
       DetachInputDevice(path);
 
     // Add initialized device to map.
     converters_[path] = converter.release();
     converters_[path]->Start();
     UpdateDirtyFlags(converters_[path]);
 
+    // Setup touch event id offsets.
+    ApplyTouchIdOffset(converters_[path]);
+
     // Sync settings to new device.
     ApplyInputDeviceSettings();
     ApplyCapsLockLed();
   }
 
   if (--pending_device_changes_ == 0)
     NotifyDevicesUpdated();
 }
 
 void InputDeviceFactoryEvdev::DetachInputDevice(const base::FilePath& path) {
@@ skipping 124 matching lines @@
                             input_device_settings_.tap_to_click_paused);
 }
 
 void InputDeviceFactoryEvdev::ApplyCapsLockLed() {
   for (const auto& it : converters_) {
     EventConverterEvdev* converter = it.second;
     converter->SetCapsLockLed(caps_lock_led_enabled_);
   }
 }
 
+void InputDeviceFactoryEvdev::ApplyTouchIdOffset(
+    EventConverterEvdev* converter) {
+  if (converter->HasTouchscreen()) {
+    converter->SetTouchIdOffset(next_touch_id_offset_);
+    next_touch_id_offset_ += converter->GetTouchPoints();
+  }
+}
+
 void InputDeviceFactoryEvdev::UpdateDirtyFlags(
     const EventConverterEvdev* converter) {
   if (converter->HasTouchscreen())
     touchscreen_list_dirty_ = true;
 
   if (converter->HasKeyboard())
     keyboard_list_dirty_ = true;
 
   if (converter->HasMouse())
     mouse_list_dirty_ = true;
@@ skipping 86 matching lines @@
   std::vector<int> ids;
   gesture_property_provider_->GetDeviceIdsByType(type, &ids);
   for (size_t i = 0; i < ids.size(); ++i) {
     SetGestureBoolProperty(gesture_property_provider_.get(), ids[i], name,
                            value);
   }
 #endif
 }
 
 }  // namespace ui