Make crosperf fail if 'build' field is empty.

Change-Id: Ia929969e0e82cc16f2ebd7c020b1af7e0b5c84ff
Reviewed-on: https://chrome-internal-review.googlesource.com/196107
Reviewed-by: Yunlian Jiang <yunlian@google.com>
Commit-Queue: Caroline Tice <cmtice@google.com>
Tested-by: Caroline Tice <cmtice@google.com>
1 file changed