WATCHLIST entries for serviceworkers and updates for indexed_db

NOTRY=true
TBR=alecflett,ericu

Review URL: https://codereview.chromium.org/178343004

git-svn-id: svn://svn.chromium.org/blink/trunk@167712 bbb929c8-8fbe-4397-9dbb-9b2b20218538