Revert of Revert part of "Remove serializer-specific hash table size heuristic."...

Revert of Revert part of "Remove serializer-specific hash table size heuristic." (patchset #1 id:1 of https://codereview.chromium.org/1272123002/ )

Reason for revert:
Did not fix issue it was intended to fix.

Original issue's description:
> Revert part of "Remove serializer-specific hash table size heuristic."
>
> TBR=machenbach@chromium.org
> NOTRY=true
> NOTREECHECKS=true
>
> Committed: https://crrev.com/68e5ae5282f3ba787c27ffa6e92fed6e5ff725e4
> Cr-Commit-Position: refs/heads/master@{#30021}

TBR=machenbach@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1276443002

Cr-Commit-Position: refs/heads/master@{#30022}