--- a/browser/components/tabview/test/browser_tabview_bug625269.js
+++ b/browser/components/tabview/test/browser_tabview_bug625269.js
@@ -61,16 +61,21 @@ function onTabViewShown(win) {
 
 // ----------
 function resizeWindow(win, diffX, diffY, callback) {
   let targetWidth = win.outerWidth + diffX;
   let targetHeight = win.outerHeight + diffY;
 
   (function tryResize() {
     let {outerWidth: width, outerHeight: height} = win;
-    if (width != targetWidth || height != targetHeight) {
-      win.resizeTo(targetWidth, targetHeight);
+    if (width == targetWidth && height == targetHeight) {
+      executeSoon(callback);
+      return;
+    }
+
+    win.addEventListener("resize", function onResize() {
+      win.removeEventListener("resize", onResize);
       executeSoon(tryResize);
-    } else {
-      callback();
-    }
+    });
+
+    win.resizeTo(targetWidth, targetHeight);
   })();
 }