Fetcher: Use ResourceFetcher::isControlledByServiceWorker for cleanup


BUG=388375
TEST=n/a

Review URL: https://codereview.chromium.org/653813002

git-svn-id: svn://svn.chromium.org/blink/trunk@183727 bbb929c8-8fbe-4397-9dbb-9b2b20218538