Revert "Remove resetScrollbars"

This reverts commit ebcbf43b12652bf96a1d1d94d8dbb5bdfd363ce6.

Speculative revert.

NOTRY=True
BUG=409708
TBR=skobes@chromium.org

Review URL: https://codereview.chromium.org/534103003

git-svn-id: svn://svn.chromium.org/blink/trunk@181275 bbb929c8-8fbe-4397-9dbb-9b2b20218538