This makes all the information that is present for GCTracer also
available to RCS.

Bug: chromium:748569
Change-Id: Ie7e8c3770b81ab1321cad08f6954492b72ef0514
Reviewed-on: https://chromium-review.googlesource.com/585427
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#47043}