Check whether a board builds a version before setting chrome version.

BUG=chromium:1004438
TEST=manual, run_tests

Change-Id: Ic189e07b19e947d76ba4770494c20a15d5365522
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1867046
Tested-by: Michael Mortensen <mmortensen@google.com>
Reviewed-by: Alex Klein <saklein@chromium.org>
Reviewed-by: David Burger <dburger@chromium.org>
Commit-Queue: Michael Mortensen <mmortensen@google.com>
diff --git a/api/controller/packages.py b/api/controller/packages.py
index f25c896..f5c84fa 100644
--- a/api/controller/packages.py
+++ b/api/controller/packages.py
@@ -128,7 +128,10 @@
   android_target_version = packages.determine_android_target(build_target)
   if android_target_version:
     output_proto.android_target_version = android_target_version
-  output_proto.chrome_version = packages.determine_chrome_version(build_target)
+  builds_chrome = packages.builds(constants.CHROME_CP, build_target)
+  if builds_chrome:
+    output_proto.chrome_version = packages.determine_chrome_version(
+        build_target)
   output_proto.platform_version = packages.determine_platform_version()
   # TODO(crbug.com/1004438): Implement remaining version fields.