TimelinePanel: REGRESSION apply window filter to the search results

Otherwise it also iterates through invisible records.

BUG=
R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/236683006

git-svn-id: svn://svn.chromium.org/blink/trunk@171475 bbb929c8-8fbe-4397-9dbb-9b2b20218538