GitLab

DevTools code needs access to platform thread id in order to collect Worker thread ids and based on them differentiate worker threads in recorded trace events.

BUG=401895

Review URL: https://codereview.chromium.org/514193002

git-svn-id: svn://svn.chromium.org/blink/trunk@181562 bbb929c8-8fbe-4397-9dbb-9b2b20218538