Backed out changeset cc96b54811f6 (bug 1357625) for failing xpcshell's test_PromiseUtils.js. r=backout

testing/modules/Assert.jsm

@@ -375,8 +375,6 @@ proto.throws = function(block, expected, message) {
  *        (mixed) Test reference to evaluate against the rejection result
  * @param message (optional)
  *        (string) Short explanation of the expected result
- * @return promise A promise that is resolved with the object the passed
- *                 promise is rejected with.
  */
 proto.rejects = function(promise, expected, message) {
   return new Promise((resolve, reject) => {
@@ -392,7 +390,7 @@ proto.rejects = function(promise, expected, message) {
           return;
         }
         this.report(false, err, expected, message);
-        resolve(err);
+        resolve();
       }
     ).then(null, reject);
   });

testing/modules/tests/xpcshell/test_assert.js

@@ -351,10 +351,6 @@ add_task(function* test_rejects() {
   // A regex to match against the message.
   yield assert.rejects(Promise.reject(new Error("oh no")), /oh no/, "rejected");
 
-  // Check the promise is resolved with the original rejection.
-  let result = yield assert.rejects(Promise.reject("oh no"));
-  equal(result, "oh no");
-
   // Failure cases:
   // An instance to check against that doesn't match.
   yield checkRejectsFails(new Error("something else"), SomeErrorLikeThing);