diff --git a/browser/devtools/styleinspector/test/head.js b/browser/devtools/styleinspector/test/head.js
index 1d3250690ad..c030cf5770a 100644
--- a/browser/devtools/styleinspector/test/head.js
+++ b/browser/devtools/styleinspector/test/head.js
@@ -506,25 +506,19 @@ function fireCopyEvent(element) {
  * polling timeouts after several tries and the promise rejects.
  * @param {String} name Optional name of the test. This is used to generate
  * the success and failure messages.
- * @param {Number} timeout Optional timeout for the validator function, in
- * milliseconds. Default is 5000.
  * @return a promise that resolves when the function returned true or rejects
  * if the timeout is reached
  */
-function waitForSuccess(validatorFn, name="untitled", timeout=5000) {
+function waitForSuccess(validatorFn, name="untitled") {
   let def = promise.defer();
   let start = Date.now();
 
   function wait(validatorFn) {
-    if ((Date.now() - start) > timeout) {
-      ok(false, "Validator function " + name + " timed out");
-      return def.reject();
-    }
     if (validatorFn()) {
       ok(true, "Validator function " + name + " returned true");
       def.resolve();
     } else {
-      setTimeout(() => wait(validatorFn), 100);
+      setTimeout(() => wait(validatorFn), 200);
     }
   }
   wait(validatorFn);