backport a patch from upstream to fix a test error.

Backport commit 0b10be4faf97396c88746f932b55bc3d2fb2d907 to
fix a the "ERROR: no fileid for" error in unittest.

BUG=None
TEST=the error is gone.

Change-Id: I1c4548cad240fefba1af480b0598aca2457c652d
Reviewed-on: https://chromium-review.googlesource.com/197891
Reviewed-by: Han Shen <shenhan@google.com>
Commit-Queue: Yunlian Jiang <yunlian@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>