Bug 1822876: Add H3 ECH Telemetry. r=kershaw,necko-reviewers
This patch adds telemetry which records when H3 connections succeed / fail
and what kind of ECH they used. Our H3 ECH tests are extended to test these
different modes and that the telemetry is recorded correctly.
Differential Revision:
https://phabricator.services.mozilla.com/D172813
[DEFAULT]
subsuite = screenshots
support-files =
../head.js
[browser_primaryUI.js]
skip-if = os == 'mac' # macosx1014 times out, see bug 1570102