[manifest] Issue a developer warning if density is present but invalid. (#285)

You can merge this Pull Request by running:

  git pull https://github.com/mounirlamouri/manifest icon_density_warning

Or you can view, comment on it, or merge it online at:

  https://github.com/w3c/manifest/pull/285

-- Commit Summary --

  * Issue a developer warning if density is present but invalid.

-- File Changes --

    M index.html (16)

-- Patch Links --

https://github.com/w3c/manifest/pull/285.patch
https://github.com/w3c/manifest/pull/285.diff

---
Reply to this email directly or view it on GitHub:
https://github.com/w3c/manifest/pull/285