[DevTools] Remove unnecessary scrollbar in settings.
[DevTools] Remove unnecessary scrollbar in settings.

BUG=353961
TBR=vsevik@chromium.org

Review URL: https://codereview.chromium.org/206373002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@169646 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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