
This is part of the process to help migrate base::JSONReader::Read() to return base::Optional<base::Value>. Do the same for ReadAndReturnError() and ReadToValue(). BUG=925165 TBR=sdefresne@chromium.org Change-Id: I3a6b5b5d581ece4771f1525e465aae7af20afddf Reviewed-on: https://chromium-review.googlesource.com/c/1476093 Reviewed-by: Lei Zhang <thestig@chromium.org> Commit-Queue: Lei Zhang <thestig@chromium.org> Cr-Commit-Position: refs/heads/master@{#632876}