Make compatible with Firefox 55

[ExE-Boss]

This extension uses APIs which are only available in Firefox 55+, and as such the strict_min_version has been set to 55.0. Chrome does the exact same thing with minimum_chrome_version.

What my comment on #118 says:

I recommend looking at the following resources:

• https://developer.mozilla.org/Add-ons/WebExtensions/Porting_a_Google_Chrome_extension
• https://developer.mozilla.org/Add-ons/WebExtensions/Porting_a_legacy_Firefox_add-on
• https://developer.mozilla.org/Add-ons/WebExtensions/WebExtensions_and_the_Add-on_ID
• https://developer.mozilla.org/Add-ons/WebExtensions/Publishing_your_WebExtension
• https://developer.mozilla.org/Add-ons/WebExtensions/Browser_support_for_JavaScript_APIs
  (For determining the minimum supported Firefox version)

Add-on ID and the minimum supported Firefox version

Since this addon has been published to AMO in the past, it is recommended that you set the Add-on ID to what it was in the legacy version.

This is achieved by adding the applications key to manifest.json:

"applications": {
	"gecko": {
		// This is the Add-on ID as it was
		// in the SDK version of the Add-on:
		"id": "jid1-DMjSwVBPnk7a1Q@jetpack",

		// This is the minimum Firefox version that supports
		// all the APIs needed by this WebExtension.
		// I have looked through the source code,
		// and it should be correct. (The `permissions` API
		// will be implemented in Firefox 55 (Bug 1197420))
		"strict_min_version": "55.0"

		// If you don’t care about the `permissions` API,
		// then you need to set `strict_min_version` to `52.0`
		// and create a dummy version of `PermissionsService`
		// for the Firefox version that auto-resolves
		// all Promises to `undefined` until Firefox 55.0
		// gets released.
	}
}

Blocked by:

• https://bugzilla.mozilla.org/show_bug.cgi?id=1197420

---

Moved from #128

[EvertEt]

https://stackoverflow.com/a/37132274
#132 (comment)