Bug 1376602 - Part 2: Add WebCompat Go Faster modules to browser_startup tests. r=Felipe

MozReview-Commit-ID: Ic1tpivC7Na

--HG--
extra : rebase_source : 6d45e4fd0f1f430aa108fc9a1eb802087fef484c

browser/base/content/test/performance/browser_startup.js

@@ -65,6 +65,8 @@ const startupPhases = {
     ]),
     modules: new Set([
       "chrome://webcompat-reporter/content/WebCompatReporter.jsm",
+      "chrome://webcompat/content/data/ua_overrides.jsm",
+      "chrome://webcompat/content/lib/ua_overrider.jsm",
       "resource:///modules/AboutNewTab.jsm",
       "resource:///modules/BrowserUITelemetry.jsm",
       "resource:///modules/BrowserUsageTelemetry.jsm",