system_api: add technology field in battery fields

Since there is a case that two different battery components only differ
in technology field, we need to add the field in D-Bus response of
Runtime Probe to describe battery in detail.

BUG=b:157972323
TEST=manual check if technology field in returned in D-Bus call to
     method "org.chromium.RuntimeProbe.ProbeCategories" with
     "categories:battery"

Change-Id: Iff28da22eec932f6f562617d07120eea7a67c4bf
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2228296
Reviewed-by: Kevin Lin <kevinptt@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Tested-by: Clark Chung <ckclark@chromium.org>
Commit-Queue: Clark Chung <ckclark@chromium.org>
(cherry picked from commit fbcaf72257ddfc4d605e87b47a10c99f702596ae)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2249554
Reviewed-by: Clark Chung <ckclark@chromium.org>
diff --git a/system_api/dbus/runtime_probe/runtime_probe.proto b/system_api/dbus/runtime_probe/runtime_probe.proto
index b78d5f7..3e6ec38 100644
--- a/system_api/dbus/runtime_probe/runtime_probe.proto
+++ b/system_api/dbus/runtime_probe/runtime_probe.proto
@@ -95,6 +95,10 @@
     // http://sbs-forum.org/specs/sbdat110.pdf.
     // The value is calculated by ((year-1980) * 512 + month * 32 + day).
     int32 manufacture_date_smart = 14;
+    // Technology is defined in
+    // /sys/class/power_supply/<supply_name>/technology section in
+    // https://www.kernel.org/doc/Documentation/ABI/testing/sysfs-class-power.
+    string technology = 15;
   }
   string name = 1;    // Component alias
   Fields values = 2;  // Component's details