diff --git a/dom/media/test/test_mediarecorder_creation_fail.html b/dom/media/test/test_mediarecorder_creation_fail.html
index 903bf1cc70c5..3c7498a09016 100644
--- a/dom/media/test/test_mediarecorder_creation_fail.html
+++ b/dom/media/test/test_mediarecorder_creation_fail.html
@@ -21,7 +21,7 @@ function startTest() {
 
   mediaRecorder.onerror = function (e) {
     is(callbackStep, 0, 'should fired onstop callback');
-    is(e.name, 'GenericError', 'error name should be GenericError');
+    is(e.error.name, 'UnknownError', 'error name should be UnknownError');
     is(mediaRecorder.mimeType, '', 'mimetype should be empty');
     is(mediaRecorder.state, 'recording', 'state is recording');
     info('onerror callback fired');
diff --git a/dom/media/test/test_mediarecorder_getencodeddata.html b/dom/media/test/test_mediarecorder_getencodeddata.html
index 426552ce73b5..dbd1c58d825d 100644
--- a/dom/media/test/test_mediarecorder_getencodeddata.html
+++ b/dom/media/test/test_mediarecorder_getencodeddata.html
@@ -30,7 +30,7 @@ SpecialPowers.pushPrefEnv({"set": [["media.ogg.enabled", false]]},
         //fires again, so set it to null to avoid failures
         mediaRecorder.ondataavailable = null;
         SimpleTest.finish();
-      }
+      };
       mediaRecorder.ondataavailable = function(evt) {
         ondataavailableFired = true;
         ok(evt instanceof BlobEvent,
@@ -43,16 +43,18 @@ SpecialPowers.pushPrefEnv({"set": [["media.ogg.enabled", false]]},
            'Blob data received should have type = ' + expectedMimeType);
         is(evt.target.mimeType, expectedMimeType,
            'Mime type in ondataavailable = ' + expectedMimeType);
-      }
+      };
       mediaRecorder.onerror = function(evt) {
-        ok(evt instanceof RecordErrorEvent,
+        ok(evt instanceof MediaRecorderErrorEvent,
           'Events fired from onerror should be RecordErrorEvent');
         is(evt.type, 'error',
-           'Event type should onerror');
-        is(evt.name, 'GenericError',
-           'Event name is GenericError');
+           'Event type is error');
+        ok(evt.error instanceof DOMException,
+          'Events fired from onerror should have a DOMException in their error member');
+        is(evt.error.name, 'UnknownError', 'Error name should be UnknownError.');
+        is(evt.error.message, 'The operation failed for an unknown transient reason');
         onErrorFired = true;
-      }
+      };
       mediaRecorder.start(0);
       is(mediaRecorder.state, 'recording', 'Media recorder should be recording');
       is(mediaRecorder.stream, stream,
diff --git a/dom/media/test/test_mediarecorder_principals.html b/dom/media/test/test_mediarecorder_principals.html
index 3c09a7b10058..4536c767ea38 100644
--- a/dom/media/test/test_mediarecorder_principals.html
+++ b/dom/media/test/test_mediarecorder_principals.html
@@ -89,9 +89,9 @@ function testPrincipals(resource) {
       hasStopped = new Promise(resolve => rec.onstop = resolve);
       video.play();
     })
-    .then(() => ok(true, msgNoThrow), e => is(e.name, null, msgNoThrow))
+    .then(() => ok(true, msgNoThrow), e => is(e.error.name, null, msgNoThrow))
     .then(() => Promise.race([
-      new Promise((_, reject) => rec.onerror = e => reject(new DOMException("", e.name))),
+      new Promise((_, reject) => rec.onerror = e => reject(e.error)),
       hasEnded
     ]))
     .then(() => ok(false, msgSecErr), e => is(e.name, "SecurityError", msgSecErr))
diff --git a/dom/media/test/test_mediarecorder_unsupported_src.html b/dom/media/test/test_mediarecorder_unsupported_src.html
index cbbc82e7d6b9..17580a613642 100644
--- a/dom/media/test/test_mediarecorder_unsupported_src.html
+++ b/dom/media/test/test_mediarecorder_unsupported_src.html
@@ -42,7 +42,7 @@ function startTest() {
           }
         }
         ok(callbackStep < 3, 'onerror callback fired as expected.');
-        is(e.name, 'GenericError', 'Error name should be GenericError.');
+        is(e.error.name, 'UnknownError', 'Error name should be UnknownError.');
         is(mediaRecorder.mimeType, '', 'mimetype should be empty');
         is(mediaRecorder.state, 'recording', 'state is recording');
         info('onerror callback fired');