Fix Crosperf's ETA bug.

Sometimes crosperf shows a negative number for ETA.  This fixes that.

BUG=None
TEST=Force the bug to happen; tested with and without the fix.

Change-Id: I0c8c909a944ad3cf25b8c5416f93ddc0b860a03d
Reviewed-on: https://chrome-internal-review.googlesource.com/157125
Reviewed-by: Han Shen <shenhan@google.com>
Reviewed-by: Yunlian Jiang <yunlian@google.com>
Commit-Queue: Caroline Tice <cmtice@google.com>
Tested-by: Caroline Tice <cmtice@google.com>
1 file changed