Bug 1914961 - feat(relay): Add entrypoint experiment params to signup url r=credential-management-reviewers,dimi

Differential Revision: https://phabricator.services.mozilla.com/D232063

toolkit/components/passwordmgr/test/browser/browser_relay_signup_flow_showToAllBrowsers.js

@@ -349,11 +349,15 @@ add_task(
 add_task(
   async function test_unauthenticated_browser_use_email_mask_opens_fxa_signin() {
     // We need the configured signup url to set up a mock server to respond to
-    // the proper path value.
+    // the proper path value. Note: this test is effectively hard-coded to the "control" variation
     const fxaSigninUrlString =
       await gFxAccounts.constructor.config.promiseConnectAccountURI(
         "relay_integration",
-        { service: "relay" }
+        {
+          service: "relay",
+          entrypoint_experiment: "first_offer_version",
+          entrypoint_variation: "control",
+        }
       );
     const fxaSigninURL = new URL(fxaSigninUrlString);
     // Now that we have a URL object, we can use its components

toolkit/components/satchel/integrations/FirefoxRelay.sys.mjs

@@ -697,6 +697,8 @@ class RelayOffered {
             "relay_integration",
             {
               service: "relay",
+              entrypoint_experiment: "first_offer_version",
+              entrypoint_variation: treatment,
             }
           );
         browser.ownerGlobal.openWebLinkIn(fxaUrl, "tab");