Tails Verification: Migrate DAVE to Web Extensions and support Chrome

Originally created by @Anonymous on #12328 (Redmine)

This should happen by November 14 2017 [1].

Some useful information:

“WebExtensions can only access web content by injecting separate scripts into web pages and communicating with them using a messaging API” (details at [3]).

At first glance, all the nsI* APIs we use seem to still be available. Note that I am not sure what
kind of add-on DAVE is, among the list of options available: overlay add-ons, bootstrapped add-ons, and SDK add-ons. According to Mozilla’s compatibility checker [2], it’s a “XUL or XPCOM add-on”, but I don’t know for sure how to interpret this, and it seems to determine quite a bit how the porting work will look like.

There are “Office Hours Support for Transitioning and Porting to WebExtensions” [4]; available options include IRC, a web forum and a mailing list.

[1] https://blog.mozilla.org/addons/2017/02/16/the-road-to-firefox-57-compatibility-milestones/
[2] https://compatibility-lookup.services.mozilla.com/
[3] https://developer.mozilla.org/en-US/Add-ons/WebExtensions/Comparison_with_XUL_XPCOM_extensions
[4] https://blog.mozilla.org/addons/2017/03/09/office-hours-support-transitioning-porting-webextensions/

Subtasks

• #11604 (closed)
• #11797 (closed)
• #12005 (closed)
• #12581 (closed)
• #12683 (closed)
• #13543 (closed)
• #14627 (closed)
• #14628 (closed)
• #14629 (closed)
• #14630 (closed)
• #14815 (closed)
• #14912 (closed)
• #14921 (closed)
• sysadmin#14934 (closed)
• #14945 (closed)
• #14961 (closed)
• #14977 (closed)
• sysadmin#14979 (closed)
• sysadmin#14980 (closed)
• #14997 (closed)
• #14998 (closed)
• #15017 (closed)
• #15056 (closed)
• #15057 (closed)
• #15058 (closed)
• #15059 (closed)
• #15060 (closed)
• #15061 (closed)
• #15062 (closed)
• #15063 (closed)
• #15133 (closed)
• #15188 (closed)
• #15367 (closed)
• #15438 (closed)
• #15443 (closed)

Related issues

• Related to #10640 (closed)
• Related to #8531 (closed)