Build API: TestService/BuildTargetUnitTest method cleanup.

BUG=chromium:954609, b:130906048
TEST=run_tests

Change-Id: If2665e7dcddfb11a6733df158b39924cad45760c
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1602932
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: David Burger <dburger@chromium.org>
Commit-Queue: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/controller_util.py b/api/controller/controller_util.py
index b12f952..17156ee 100644
--- a/api/controller/controller_util.py
+++ b/api/controller/controller_util.py
@@ -16,7 +16,19 @@
   path = chroot_message.path
   cache_dir = chroot_message.cache_dir
 
-  return chroot_lib.Chroot(path=path, cache_dir=cache_dir)
+  use_flags = [u.flag for u in chroot_message.env.use_flags]
+  features = [f.feature for f in chroot_message.env.features]
+
+  env = {}
+  if use_flags:
+    env['USE'] = ' '.join(use_flags)
+
+  # TODO(saklein) Remove the default when fully integrated in recipes.
+  env['FEATURES'] = 'separatedebug'
+  if features:
+    env['FEATURES'] = ' '.join(features)
+
+  return chroot_lib.Chroot(path=path, cache_dir=cache_dir, env=env)
 
 
 def CPVToPackageInfo(cpv, package_info):