Convert away from JSONReader::ReadDeprecated in devtools/

Use the new JSONReader::Read API that use the new API of
base::Value (move semantic) and convert the surrounding
code to the new API at the same time.

Bug: 925165, 646113, 954874
Change-Id: I4742dd1106db6e638f650091c81ddb65a383cadb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1578551
Auto-Submit: Pâris Meuleman <pmeuleman@chromium.org>
Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Reviewed-by: Andrey Kosyakov <caseq@chromium.org>
Commit-Queue: Pâris Meuleman <pmeuleman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657174}
7 files changed