Trying to reduce use of our self-baked data structures.

Bug: v8:7570
Change-Id: I3c8598ece74b6434c8baa69810a384b5209dd107
Reviewed-on: https://chromium-review.googlesource.com/1032442Reviewed-by: Yang Guo <yangguo@chromium.org>
Commit-Queue: Peter Marshall <petermarshall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52842}