Bug 1500070 - Avoid using about:debugging in generic about: page tests. r=jdescottes

Opening about:debugging may lead to pending listAddons requests.
Tests that open about:debugging should be careful to wait for the end
of these requests, which this test doesn't do.

MozReview-Commit-ID: 6YyfdW78kOS

Depends on D8828

Differential Revision: https://phabricator.services.mozilla.com/D8867

--HG--
extra : moz-landing-system : lando

browser/components/contextualidentity/test/browser/browser_aboutURLs.js

@@ -16,6 +16,8 @@ add_task(async function() {
     "telemetry",
     // about:downloads causes a shutdown leak with stylo-chrome. bug 1419943.
     "downloads",
+    // about:debugging requires specific wait code for internal pending RDP requests.
+    "debugging",
   ];
 
   for (let cid in Cc) {

devtools/client/shared/test/browser_link.js

@@ -21,11 +21,11 @@ add_task(async function() {
   is(gBrowser.selectedBrowser.currentURI.spec, TEST_URI,
     "openDocLink opened a tab with the expected url");
 
-  info("Open trusted link to about:debugging");
-  openTrustedLink("about:debugging");
+  info("Open trusted link to about:config");
+  openTrustedLink("about:config");
   await BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser);
 
-  is(gBrowser.selectedBrowser.currentURI.spec, "about:debugging",
+  is(gBrowser.selectedBrowser.currentURI.spec, "about:config",
     "openTrustedLink opened a tab with the expected url");
 
   await removeTab(gBrowser.selectedTab);