Add optionalSW parameter

This parameter allows the page to continue loading even if the service
worker does not register correctly. This happens sometimes when
embedding the page via an iframe.

Change-Id: I3eeb866a47673f2a0f1357ec20b6de6c549c7f4c
2 files changed
tree: 732c7c96de3d8c6085c7fbd345e1fb8c737ab290
  1. concerts/
  2. css/
  3. img/
  4. js/
  5. tools/
  6. index.html
  7. manifest.json
  8. robots.txt
  9. sw.js