Revert "[linux] Improved the wrapper for the D-Bus screensaver service."

This reverts commit a7fa7364dde651afdc364562cb60ddf3674dc645.

Reason for revert: causes crashes when building with is_chrome_branded

Original change's description:
> [linux] Improved the wrapper for the D-Bus screensaver service.
>
> This is a follow-up to [1].  Here the wrapper class is improved so it no
> longer uses blocking calls to D-Bus.
>
> [1] https://chromium-review.googlesource.com/c/chromium/src/+/2929877
>
> Bug: 1098202
> Change-Id: I8a71e5f56a1dec4836010889dde1be7231ea9e7f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2931463
> Reviewed-by: Scott Violet <sky@chromium.org>
> Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
> Commit-Queue: Alexander Dunaev <adunaev@igalia.com>
> Cr-Commit-Position: refs/heads/master@{#890086}

Bug: 1098202
Change-Id: I20df2de71cb074990f08039fd7578c390ed20169
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2951422
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Cr-Commit-Position: refs/heads/master@{#891113}