This is a reland of 1ba5d5ba
without any changes.

TBR=jarin@chromium.org

Original change's description:
> Clean up DependentCode class.
>
> Also move some helpers there.
>
> Bug: v8:7902
> Change-Id: I1ef3d1e8317102afae2861382e9ba60b0ef6bba4
> Reviewed-on: https://chromium-review.googlesource.com/1121461
> Commit-Queue: Georg Neis <neis@chromium.org>
> Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#54179}

Bug: v8:7902
Change-Id: I9ef70b88be1b31b458a95442ff3806d651e809ee
Reviewed-on: https://chromium-review.googlesource.com/1127719Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54289}