handler/sw.js: Added an 'action' event listener; log the received file contents to console.
handler/sw.js: Added an 'action' event listener; log the received file contents to console.

chromium/ballista,mgiuca/ballista,benfredwells/ballista,benfredwells/ballista,addyosmani/ballista,chromium/ballista,mgiuca/ballista,addyosmani/ballista