Add build_directory_owner_user_id/build_directory_owner_group_id to RunnerConfiguration

Author: mortenmj

pkg/proto/configuration/bb_worker/bb_worker.pb.go

@@ -380,6 +380,16 @@ message RunnerConfiguration {
   // You may need to implement a custom ActionRouter for bb_scheduler to
   // enforce this.
   uint32 maximum_consecutive_test_infrastructure_failures = 14;
+
+  // The ID of the user that owns directories contained in the build
+  // directory. This should typically be set to the user that is used by
+  // bb_runner to run actions.
+  uint32 build_directory_owner_user_id = 15;
+
+  // The ID of the group that owns directories contained in the build
+  // directory. This should typically be set to the primary group of the
+  // user that is used by bb_runner to run actions.
+  uint32 build_directory_owner_group_id = 16;
 }
 
 message CompletedActionLoggingConfiguration {