tracing: Add executable tool to export json from proto

Change-Id: Ie1634c14cb7249688e4482bff34c51dc04511ea6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1613590
Commit-Queue: ssid <ssid@chromium.org>
Reviewed-by: oysteine <oysteine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660707}
2 files changed