Revert "Record FCP++ before user input."

This reverts commit 8f40b285f693000b4a95da403e0a94339a6ef02b.

Reason for revert: This was an interim solution that has been replaced by Max's proper solution: https://chromium-review.googlesource.com/c/chromium/src/+/1399282

Original change's description:
> Record FCP++ before user input.
>
> This is an initial, experimental implementation to determine if
> we should do a more complete implementation in the render process.
>
> Previous privacy review for largest text/image paint: Privacy review: https://docs.google.com/document/d/1LJnD-INFo7UnvPyB6C-tzpJ3BLK9rYA2SbnwTcsyeTs/edit
>
> Change-Id: Ica826e974fee39c5696230fd3d9ffdee42786da8
> Bug: 915295
> Reviewed-on: https://chromium-review.googlesource.com/c/1378409
> Commit-Queue: Bryan McQuade <bmcquade@chromium.org>
> Reviewed-by: Timothy Dresser <tdresser@chromium.org>
> Reviewed-by: Charlie Harrison <csharrison@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#616844}

Bug: 915295
Change-Id: I51f16962115906ca4b7b91226fe7eee68d26ee34
Reviewed-on: https://chromium-review.googlesource.com/c/1416152
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
Commit-Queue: Bryan McQuade <bmcquade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623458}
4 files changed