GetBuildMetadata: Add fingerprints to api/controller and service layer.

BUG=chromium:1071620
TEST=manual, run_tests

Change-Id: If4e6aa2b713112de3c978c48cdb6e54aa589e61a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/2204243
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_unittest.py b/api/controller/packages_unittest.py
index cf6a66b..354d7cc 100644
--- a/api/controller/packages_unittest.py
+++ b/api/controller/packages_unittest.py
@@ -563,6 +563,9 @@
         'caroline_v1.9.370-e8b9bd2')
     self.PatchObject(packages_service, 'get_firmware_versions',
                      return_value=fw_versions)
+    fingerprints = ['fingerprint1', 'fingerprint2']
+    self.PatchObject(packages_service, 'find_fingerprints',
+                     return_value=fingerprints)
     request = self._GetRequest(board='betty')
     packages_controller.GetBuilderMetadata(request, self.response,
                                            self.api_config)
@@ -596,6 +599,12 @@
     self.assertEqual(
         self.response.build_target_metadata[0].kernel_version,
         '4.4.223-r2209')
+    self.assertEqual(
+        len(self.response.build_target_metadata[0].fingerprints),
+        2)
+    self.assertEqual(
+        self.response.build_target_metadata[0].fingerprints,
+        fingerprints)
 
 
 class HasChromePrebuiltTest(cros_test_lib.MockTestCase, ApiConfigMixin):