Add GetBuildMetadata firmware/ec_firmware values and service method.

BUG=chromium:1071620
TEST=manual, run_tests

Change-Id: I8e754953e42a88cbb16be3af474a84a25a93802d
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2186070
Reviewed-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Michael Mortensen <mmortensen@google.com>
Tested-by: Michael Mortensen <mmortensen@google.com>
diff --git a/api/controller/packages.py b/api/controller/packages.py
index ef3c289..a788672 100644
--- a/api/controller/packages.py
+++ b/api/controller/packages.py
@@ -234,6 +234,10 @@
 
   # TODO(crbug/1071620): Add service layer calls to fill out the rest of
   # build_target_metadata and model_metadata.
+  fw_versions = packages.determine_firmware_versions(build_target)
+  build_target_metadata.main_firmware_version = fw_versions.main_fw_version
+  build_target_metadata.ec_firmware_version = fw_versions.ec_fw_version
+
 
 def _HasPrebuiltSuccess(_input_proto, output_proto, _config):
   """The mock success case for HasChromePrebuilt."""