DevTools: gardening. rebaseline timeline-frames.html

BUG=407915
TBR= caseq@chromium.org

Review URL: https://codereview.chromium.org/625833002

git-svn-id: svn://svn.chromium.org/blink/trunk@183180 bbb929c8-8fbe-4397-9dbb-9b2b20218538