Negative values from TimeUntilNextProcess indicate that the module
wanted to run sooner than possible, not that an invalid error code was
returned. As such it's not a contract error.
BUG=webrtc:4879
NOTRY=true
Review URL: https://codereview.webrtc.org/1257833004
Cr-Commit-Position: refs/heads/master@{#9740}