Handle empty test specs.

BUG=chromium:397279
TEST=manual

Change-Id: I6f6cc838dd5e3f2c0e32c2c5e1d46d4ba649c277
Reviewed-on: https://chromium-review.googlesource.com/213205
Commit-Queue: Achuith Bhandarkar <achuith@chromium.org>
Tested-by: Achuith Bhandarkar <achuith@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
1 file changed