Revert of [Extensions] Finish freezing schema (patchset #1 id:1 of https://codereview.chromium.org/1928783005/ )

Reason for revert:
Compile failure

Original issue's description:
> [Extensions] Finish freezing schema
>
> BUG=604901
> BUG=603725
> BUG=591164
>
> Review URL: https://codereview.chromium.org/1906593002
>
> Cr-Commit-Position: refs/heads/master@{#388945}
> (cherry picked from commit 5fb2548448bd1b76a59d941b729d7a7f90d53bc8)
>
> Committed: https://chromium.googlesource.com/chromium/src/+/ed087c3f125239baa798fbbceded413d529674ed

TBR=
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=604901

Review-Url: https://codereview.chromium.org/1928193002
Cr-Commit-Position: refs/branch-heads/2704@{#301}
Cr-Branched-From: 6e53600def8f60d8c632fadc70d7c1939ccea347-refs/heads/master@{#386251}
11 files changed