Update controller_util to handle goma_config.chromeos_goma_dir.

This include regenerating test_pb2.py and common_pb2.py by
running api/compile_build_api_proto and updating unit tests to
validate calls to goma with and without chromeos_goma_dir.

BUG=chromium:999670
TEST=manual, run_tests

Change-Id: I805e800551ef6199674b94bccf10786ef6db2586
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1838305
Tested-by: Michael Mortensen <mmortensen@google.com>
Auto-Submit: Michael Mortensen <mmortensen@google.com>
Reviewed-by: Alex Klein <saklein@chromium.org>
Commit-Queue: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/controller_util.py b/api/controller/controller_util.py
index 630be1f..af0cb6b 100644
--- a/api/controller/controller_util.py
+++ b/api/controller/controller_util.py
@@ -59,9 +59,11 @@
 
   goma = None
   if chroot_message.goma.goma_dir:
+    chromeos_goma_dir = chroot_message.goma.chromeos_goma_dir or None
     goma = goma_util.Goma(chroot_message.goma.goma_dir,
                           chroot_message.goma.goma_client_json,
-                          stage_name='BuildAPI')
+                          stage_name='BuildAPI',
+                          chromeos_goma_dir=chromeos_goma_dir)
 
   return Chroot(path=path, cache_dir=cache_dir, chrome_root=chrome_root,
                 env=env, goma=goma)