Clarify service worker member, and when it installs

[marcoscaceres]

@GrosSacASac wrote:

If I understand correctly, the service worker declaration inside the manifest has no consequence unless the web app is installed without directly visting the web app url.(with an web app store ?)

I ask because I have an app where the service worker is only installed after the users checks the checkbox USE OFFLINE. I don't want the manifest to install the service worker on normal page load without user consent first.

I came here because https://www.w3.org/TR/appmanifest/#serviceworker-member words are confusing.

[christianliebel]

@marcoscaceres There’s a discussion in #800 on exactly this topic, so I’d suggest closing the issue here.

[mgiuca]

Closing in favour of #800.