Update TraceWrapperV8Reference

- Update class comment
- Remove Set method that takes custom callbacks as all of its uses have been
  converted to phantom handles that are cleared by the GC.

Bug: 843903
Change-Id: I3d772d6486b2908402ba9ff5df49cd796f497616
Reviewed-on: https://chromium-review.googlesource.com/c/1388426
Reviewed-by: Yuki Shiino <yukishiino@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#618762}
1 file changed