Revert of Disable elastic overscroll effect in DevTools. (patchset #1 id:1 of https://codereview.chromium.org/925903002/)

Reason for revert:
Turned out this patch is unnecessary.

Original issue's description:
> Disable elastic overscroll effect in DevTools.
>
> BUG=456546
>
> Committed: https://crrev.com/5210d618e08fc4a1ce3ab0953d7fa42a98fc8140
> Cr-Commit-Position: refs/heads/master@{#316834}

TBR=pfeldman@chromium.org,ccameron@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=456546

Review URL: https://codereview.chromium.org/963743003

Cr-Commit-Position: refs/heads/master@{#318440}
4 files changed