Remove unused member causing build failures
Remove unused member causing build failures

Setting "scrollingperformanceloggingenabled" removed in r148099
and left this field unused, causing build failures on some platforms
due to warning-as-error.

TBR=pilgrim@chromium.org
BUG=226711

Review URL: https://codereview.chromium.org/14096004

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@148106 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs