Switch timeline-decode-resize.html to using displayAsyncThen

This should hopefully deflake it. Also, swithc to using
invokeAsyncWithTimeline() and do not depend on Timeline
records arriving before the recording is stopped.

TBR=loislo@chromium.org

Review URL: https://codereview.chromium.org/418033002

git-svn-id: svn://svn.chromium.org/blink/trunk@178851 bbb929c8-8fbe-4397-9dbb-9b2b20218538