ozone: Map TouchEvent::touch_id_ into expected range

ui/events/ozone/evdev/input_device_factory_evdev.cc

Index: ui/events/ozone/evdev/input_device_factory_evdev.cc
diff --git a/ui/events/ozone/evdev/input_device_factory_evdev.cc b/ui/events/ozone/evdev/input_device_factory_evdev.cc
index 988047ba7097a004ea7d9977fc0ba8585028f743..02af807fa70d3c49014147968203e49a9705710b 100644
--- a/ui/events/ozone/evdev/input_device_factory_evdev.cc
+++ b/ui/events/ozone/evdev/input_device_factory_evdev.cc
@@ -191,6 +191,7 @@ InputDeviceFactoryEvdev::InputDeviceFactoryEvdev(
       mouse_list_dirty_(false),
       touchpad_list_dirty_(false),
       caps_lock_led_enabled_(false),
+      next_touch_id_offset_(0),
       weak_ptr_factory_(this) {
 }
 
@@ -245,6 +246,9 @@ void InputDeviceFactoryEvdev::AttachInputDevice(
     converters_[path]->Start();
     UpdateDirtyFlags(converters_[path]);
 
+    // Setup touch event id offsets.
+    ApplyTouchIdOffset(converters_[path]);
+
     // Sync settings to new device.
     ApplyInputDeviceSettings();
     ApplyCapsLockLed();
@@ -389,6 +393,14 @@ void InputDeviceFactoryEvdev::ApplyCapsLockLed() {
   }
 }
 
+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())