exo: gamepad: Send correct axis code

In the previous CL https://crrev.com/c/1624385 I forwarded wrong axis
indices to ARC. In order to forward correct evdev ABS_CNT axis indices,
you have to also keep raw indices in ui::GamepadDevice::Axis.

This is a part of the effort to improve ARC gamepad compatibility.
Design doc: go/arc-improved-gamepad

TEST=manual(--enable-features=ExoRawGamepadInfo to /etc/chrome_dev.conf)
BUG=b:130597086

Change-Id: I997b262749b413cee38af40cc498ea2b399e2904
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1631150Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Reviewed-by: Mitsuru Oshima (OOO 5/28) <oshima@chromium.org>
Commit-Queue: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664082}

components/exo/wayland/zcr_gaming_input.cc

@@ -164,11 +164,10 @@ class WaylandGamingSeatDelegate : public GamingSeatDelegate {
           GetGamepadBusType(device.type), device.vendor_id, device.product_id,
           device.version);
 
-      for (size_t i = 0; i < device.axes.size(); ++i) {
-        const auto& axis = device.axes[i];
-        zcr_gamepad_v2_send_axis_added(gamepad_resource, i, axis.min_value,
-                                       axis.max_value, axis.flat, axis.fuzz,
-                                       axis.resolution);
+      for (const auto& axis : device.axes) {
+        zcr_gamepad_v2_send_axis_added(gamepad_resource, axis.code,
+                                       axis.min_value, axis.max_value,
+                                       axis.flat, axis.fuzz, axis.resolution);
       }
       zcr_gamepad_v2_send_activated(gamepad_resource);
     } else {

ui/events/devices/gamepad_device.h

@@ -16,6 +16,9 @@ namespace ui {
 struct EVENTS_DEVICES_EXPORT GamepadDevice : public InputDevice {
   // Represents an axis of a gamepad e.g. an analog thumb stick.
   struct Axis {
+    // Gamepad axis index. Corresponds to |raw_code_| of GamepadEvent.
+    uint16_t code = 0;
+
     // See input_absinfo for the definition of these variables.
     int32_t min_value = 0;
     int32_t max_value = 0;

ui/events/ozone/evdev/gamepad_event_converter_evdev.cc

@@ -135,6 +135,7 @@ GamepadEventConverterEvdev::GamepadEventConverterEvdev(
     abs_info = devinfo.GetAbsInfoByCode(code);
     if (devinfo.HasAbsEvent(code)) {
       ui::GamepadDevice::Axis axis;
+      axis.code = code;
       axis.min_value = abs_info.minimum;
       axis.max_value = abs_info.maximum;
       axis.flat = abs_info.flat;