diff --git a/testing/mochitest/BrowserTestUtils/BrowserTestUtils.jsm b/testing/mochitest/BrowserTestUtils/BrowserTestUtils.jsm
index 49a003ab3964..0533f68e8784 100644
--- a/testing/mochitest/BrowserTestUtils/BrowserTestUtils.jsm
+++ b/testing/mochitest/BrowserTestUtils/BrowserTestUtils.jsm
@@ -96,7 +96,7 @@ this.BrowserTestUtils = {
    *
    * @param {tabbrowser} tabbrowser
    *        The tabbrowser to open the tab new in.
-   * @param {string} opening
+   * @param {string} opening (or url)
    *        May be either a string URL to load in the tab, or a function that
    *        will be called to open a foreground tab. Defaults to "about:blank".
    * @param {boolean} waitForLoad
@@ -104,12 +104,44 @@ this.BrowserTestUtils = {
    * @param {boolean} waitForStateStop
    *        True to wait for the web progress listener to send STATE_STOP for the
    *        document in the tab. Defaults to false.
+   * @param {boolean} forceNewProcess
+   *        True to force the new tab to load in a new process. Defaults to
+   *        false.
+   * NB: tabbrowser may be an options object containing the rest of the
+   *     parameters.
    *
    * @return {Promise}
    *         Resolves when the tab is ready and loaded as necessary.
    * @resolves The new tab.
    */
-  openNewForegroundTab(tabbrowser, opening = "about:blank", aWaitForLoad = true, aWaitForStateStop = false) {
+  openNewForegroundTab(tabbrowser, ...args) {
+    let options;
+    if (tabbrowser instanceof Ci.nsIDOMXULElement) {
+      // tabbrowser is a tabbrowser, read the rest of the arguments from args.
+      let [
+        opening = "about:blank",
+        waitForLoad = true,
+        waitForStateStop = false,
+      ] = args;
+
+      options = { opening, waitForLoad, waitForStateStop };
+    } else {
+      if ("url" in tabbrowser && !("opening" in tabbrowser)) {
+        tabbrowser.opening = tabbrowser.url;
+      }
+
+      let {
+        opening = "about:blank",
+        waitForLoad = true,
+        waitForStateStop = false,
+      } = tabbrowser;
+
+      tabbrowser = tabbrowser.gBrowser;
+      options = { opening, waitForLoad, waitForStateStop };
+    }
+
+    let { opening: opening, waitForLoad: aWaitForLoad, waitForStateStop: aWaitForStateStop } = options;
+
     let tab;
     let promises = [
       BrowserTestUtils.switchTab(tabbrowser, function () {