Reland "Add chrome_cleaner sandboxed engine Mojo interfaces"

This relands commit 0a12bc8f7a25464580101a8308c6c455fe62b6d9, which was
reverted in https://chromium-review.googlesource.com/c/chromium/src/+/1186781.

This is identical to 0a12bc8f7a25464580101a8308c6c455fe62b6d9 but adds
disable_variants = true to all chrome_cleaner mojo interfaces to prevent
the blink and non-C++ variants from being built.

Original change's description:
> Add chrome_cleaner sandboxed engine Mojo interfaces
>
> R=wfh
>
> Bug: 830892
> Change-Id: I0a4b25b2ba04b65a80e2c03e9151b5ef55912432
> Reviewed-on: https://chromium-review.googlesource.com/1171737
> Commit-Queue: Joe Mason <joenotcharles@chromium.org>
> Reviewed-by: Will Harris <wfh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#585025}

Bug: 830892
Change-Id: Ib476d03e0c3aba44c55bb0b4b26b6c38369e6b12
Reviewed-on: https://chromium-review.googlesource.com/1187004
Reviewed-by: Ken Rockot <rockot@chromium.org>
Reviewed-by: Joe Mason <joenotcharles@chromium.org>
Commit-Queue: Joe Mason <joenotcharles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#586683}
9 files changed