Bug 1303298 - Work around intermittent browser_mixed_content_cert_override.js. r=nhnt11

MozReview-Commit-ID: 5srDm58jz5M

--HG--
extra : rebase_source : 5e8a53e59bab056072f8ccc55f778e8cfdfab11a

browser/base/content/test/general/head.js

@@ -1023,8 +1023,17 @@ function* loadBadCertPage(url) {
                              "cert-exception-ui-ready", false);
   });
 
-  yield BrowserTestUtils.loadURI(gBrowser.selectedBrowser, url);
-  yield promiseErrorPageLoaded(gBrowser.selectedBrowser);
+  // Sometimes clearing the cert override is not immediately picked up,
+  // so we reload until we are on an actual cert error page.
+  yield BrowserTestUtils.waitForCondition(function*() {
+    yield BrowserTestUtils.loadURI(gBrowser.selectedBrowser, url);
+    yield promiseErrorPageLoaded(gBrowser.selectedBrowser);
+    let isErrorPage = yield ContentTask.spawn(gBrowser.selectedBrowser, null, function*() {
+      return content.document.documentURI.startsWith("about:certerror");
+    });
+    return isErrorPage;
+  }, "Could not load error page", 1000);
+
   yield ContentTask.spawn(gBrowser.selectedBrowser, null, function*() {
     content.document.getElementById("exceptionDialogButton").click();
   });