DevTools: NetworkPanel: filtered-out rows are not hidden.

Regressed by https://codereview.chromium.org/288973004

BUG=376705
NOTRY=true
TBR=vsevik

Review URL: https://codereview.chromium.org/293983021

git-svn-id: svn://svn.chromium.org/blink/trunk@174677 bbb929c8-8fbe-4397-9dbb-9b2b20218538