--- a/dom/events/EventDispatcher.cpp
+++ b/dom/events/EventDispatcher.cpp
@@ -20,28 +20,26 @@
 #include "DeviceMotionEvent.h"
 #include "DragEvent.h"
 #include "GeckoProfiler.h"
 #include "KeyboardEvent.h"
 #include "mozilla/ContentEvents.h"
 #include "mozilla/dom/CloseEvent.h"
 #include "mozilla/dom/CustomEvent.h"
 #include "mozilla/dom/DeviceOrientationEvent.h"
-#include "mozilla/dom/ErrorEvent.h"
 #include "mozilla/dom/EventTarget.h"
 #include "mozilla/dom/FocusEvent.h"
 #include "mozilla/dom/HashChangeEvent.h"
 #include "mozilla/dom/InputEvent.h"
 #include "mozilla/dom/MessageEvent.h"
 #include "mozilla/dom/MouseScrollEvent.h"
 #include "mozilla/dom/MutationEvent.h"
 #include "mozilla/dom/NotifyPaintEvent.h"
 #include "mozilla/dom/PageTransitionEvent.h"
 #include "mozilla/dom/PointerEvent.h"
-#include "mozilla/dom/PopStateEvent.h"
 #include "mozilla/dom/RootedDictionary.h"
 #include "mozilla/dom/ScrollAreaEvent.h"
 #include "mozilla/dom/SimpleGestureEvent.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/StorageEvent.h"
 #include "mozilla/dom/TimeEvent.h"
 #include "mozilla/dom/TouchEvent.h"
 #include "mozilla/dom/TransitionEvent.h"
@@ -1057,28 +1055,16 @@ EventDispatcher::CreateEvent(EventTarget
   if (aEventType.LowerCaseEqualsLiteral("beforeunloadevent")) {
     LOG_EVENT_CREATION(BEFOREUNLOADEVENT);
     return NS_NewDOMBeforeUnloadEvent(aOwner, aPresContext, nullptr);
   }
   if (aEventType.LowerCaseEqualsLiteral("scrollareaevent")) {
     LOG_EVENT_CREATION(SCROLLAREAEVENT);
     return NS_NewDOMScrollAreaEvent(aOwner, aPresContext, nullptr);
   }
-  // XXXkhuey Chrome supports popstateevent here, even though it provides no
-  // initPopStateEvent method.  This is nuts ... but copying it is unlikely to
-  // break the web.
-  if (aEventType.LowerCaseEqualsLiteral("popstateevent")) {
-    LOG_EVENT_CREATION(POPSTATEEVENT);
-    AutoJSContext cx;
-    RootedDictionary<PopStateEventInit> init(cx);
-    RefPtr<Event> event =
-      PopStateEvent::Constructor(aOwner, EmptyString(), init);
-    event->MarkUninitialized();
-    return event.forget();
-  }
   if (aEventType.LowerCaseEqualsLiteral("touchevent") &&
       TouchEvent::PrefEnabled(nsContentUtils::GetDocShellForEventTarget(aOwner))) {
     LOG_EVENT_CREATION(TOUCHEVENT);
     return NS_NewDOMTouchEvent(aOwner, aPresContext, nullptr);
   }
   if (aEventType.LowerCaseEqualsLiteral("hashchangeevent")) {
     LOG_EVENT_CREATION(HASHCHANGEEVENT);
     HashChangeEventInit init;
@@ -1093,24 +1079,16 @@ EventDispatcher::CreateEvent(EventTarget
   }
   if (aEventType.LowerCaseEqualsLiteral("storageevent")) {
     LOG_EVENT_CREATION(STORAGEEVENT);
     RefPtr<Event> event =
       StorageEvent::Constructor(aOwner, EmptyString(), StorageEventInit());
     event->MarkUninitialized();
     return event.forget();
   }
-  if (aEventType.LowerCaseEqualsLiteral("errorevent")) {
-    LOG_EVENT_CREATION(ERROREVENT);
-    RootedDictionary<ErrorEventInit> init(RootingCx());
-    RefPtr<Event> event =
-      ErrorEvent::Constructor(aOwner, EmptyString(), init);
-    event->MarkUninitialized();
-    return event.forget();
-  }
 
   // Only allow these events for chrome
   if (aCallerType == CallerType::System) {
     if (aEventType.LowerCaseEqualsLiteral("simplegestureevent")) {
       return NS_NewDOMSimpleGestureEvent(aOwner, aPresContext, nullptr);
     }
     if (aEventType.LowerCaseEqualsLiteral("xulcommandevent")) {
       LOG_EVENT_CREATION(XULCOMMANDEVENT);

--- a/dom/events/test/test_bug517851.html
+++ b/dom/events/test/test_bug517851.html
@@ -27,29 +27,27 @@ var target = document.createElement("div
 var target2 = $("subframe").contentDocument.body;
 target.setAttribute("onerror", "++window.handledCount; return window.testReturnValue;");
 target2.setAttribute("onerror", "++window.parent.handledCount; return window.parent.testReturnValue;");
 target.setAttribute("onmouseover", "++window.handledCount; return window.testReturnValue;");
 target.setAttribute("onbeforeunload", "++window.handledCount; return window.testReturnValue;");
 target2.setAttribute("onbeforeunload", "++window.parent.handledCount; return window.parent.testReturnValue;");
 target.setAttribute("onmousemove", "++window.handledCount; return window.testReturnValue;");                     
 
-var e = document.createEvent("ErrorEvent");
-e.initEvent("error", true, true);
+var e = new ErrorEvent("error", {bubbles: true, cancelable: true});
 window.testReturnValue = true;
 is(target.dispatchEvent(e), window.testReturnValue,
    "error event should not have reverse return value handling on div!");
 is(handledCount, 1, "Wrong event count!");
 window.testReturnValue = false;
 is(target.dispatchEvent(e), window.testReturnValue,
    "error event should not have reverse return value handling on div (2)!");
 is(handledCount, 2, "Wrong event count!");
 
-var e = document.createEvent("ErrorEvent");
-e.initEvent("error", true, true);
+var e = new ErrorEvent("error", {bubbles: true, cancelable: true});
 window.testReturnValue = false;
 is(target2.dispatchEvent(e), !window.testReturnValue,
    "error event should have reverse return value handling!");
 is(handledCount, 3, "Wrong event count!");
 window.testReturnValue = true;
 is(target2.dispatchEvent(e), !window.testReturnValue,
    "error event should have reverse return value handling (2)!");
 is(handledCount, 4, "Wrong event count!");

--- a/testing/web-platform/meta/dom/events/EventTarget-dispatchEvent.html.ini
+++ b/testing/web-platform/meta/dom/events/EventTarget-dispatchEvent.html.ini
@@ -1,50 +1,6 @@
 [EventTarget-dispatchEvent.html]
   type: testharness
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (AnimationEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (CloseEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
   [If the event's initialized flag is not set, an InvalidStateError must be thrown (FocusEvent).]
     expected: FAIL
     bug: https://github.com/whatwg/dom/issues/362, 1314303
 
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (IDBVersionChangeEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (PageTransitionEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (ProgressEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (SVGZoomEvent).]
-    expected: FAIL
-    bug: 1314388
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (SVGZoomEvents).]
-    expected: FAIL
-    bug: 1314388
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (TrackEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (TransitionEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (WebGLContextEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [If the event's initialized flag is not set, an InvalidStateError must be thrown (WheelEvent).]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-

--- a/testing/web-platform/meta/dom/nodes/Document-createEvent.html.ini
+++ b/testing/web-platform/meta/dom/nodes/Document-createEvent.html.ini
@@ -1,58 +1,10 @@
 [Document-createEvent.html]
   type: testharness
-  [AnimationEvent should be an alias for AnimationEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('AnimationEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [animationevent should be an alias for AnimationEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('animationevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [ANIMATIONEVENT should be an alias for AnimationEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('ANIMATIONEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [CloseEvent should be an alias for CloseEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('CloseEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [closeevent should be an alias for CloseEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('closeevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [CLOSEEVENT should be an alias for CloseEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('CLOSEEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
   [FocusEvent should be an alias for FocusEvent.]
     expected: FAIL
     bug: https://github.com/whatwg/dom/issues/362, 1314303
 
   [createEvent('FocusEvent') should be initialized correctly.]
     expected: FAIL
     bug: https://github.com/whatwg/dom/issues/362, 1314303
 
@@ -67,184 +19,16 @@
   [FOCUSEVENT should be an alias for FocusEvent.]
     expected: FAIL
     bug: https://github.com/whatwg/dom/issues/362, 1314303
 
   [createEvent('FOCUSEVENT') should be initialized correctly.]
     expected: FAIL
     bug: https://github.com/whatwg/dom/issues/362, 1314303
 
-  [IDBVersionChangeEvent should be an alias for IDBVersionChangeEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('IDBVersionChangeEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [idbversionchangeevent should be an alias for IDBVersionChangeEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('idbversionchangeevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [IDBVERSIONCHANGEEVENT should be an alias for IDBVersionChangeEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('IDBVERSIONCHANGEEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [PageTransitionEvent should be an alias for PageTransitionEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('PageTransitionEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [pagetransitionevent should be an alias for PageTransitionEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('pagetransitionevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [PAGETRANSITIONEVENT should be an alias for PageTransitionEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('PAGETRANSITIONEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [ProgressEvent should be an alias for ProgressEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('ProgressEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [progressevent should be an alias for ProgressEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('progressevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [PROGRESSEVENT should be an alias for ProgressEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('PROGRESSEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [TrackEvent should be an alias for TrackEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('TrackEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [trackevent should be an alias for TrackEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('trackevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [TRACKEVENT should be an alias for TrackEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('TRACKEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [TransitionEvent should be an alias for TransitionEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('TransitionEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [transitionevent should be an alias for TransitionEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('transitionevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [TRANSITIONEVENT should be an alias for TransitionEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('TRANSITIONEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [WebGLContextEvent should be an alias for WebGLContextEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('WebGLContextEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [webglcontextevent should be an alias for WebGLContextEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('webglcontextevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [WEBGLCONTEXTEVENT should be an alias for WebGLContextEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('WEBGLCONTEXTEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [WheelEvent should be an alias for WheelEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('WheelEvent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [wheelevent should be an alias for WheelEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('wheelevent') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [WHEELEVENT should be an alias for WheelEvent.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
-  [createEvent('WHEELEVENT') should be initialized correctly.]
-    expected: FAIL
-    bug: https://github.com/whatwg/dom/issues/362, 1314303
-
   [Should throw NOT_SUPPORTED_ERR for pluralized non-legacy event interface "KeyEvents"]
     expected: FAIL
     bug: 1251198
 
   [Should throw NOT_SUPPORTED_ERR for pluralized non-legacy event interface "MouseScrollEvents"]
     expected: FAIL
     bug: 1251198
 

--- a/testing/web-platform/tests/dom/nodes/Document-createEvent.html
+++ b/testing/web-platform/tests/dom/nodes/Document-createEvent.html
@@ -66,32 +66,36 @@ test(function() {
 
 /*
  * The following are event interfaces which do actually exist, but must still
  * throw since they're absent from the table in the spec for
  * document.createEvent().  This list is not exhaustive, but includes all
  * interfaces that it is known some UA does or did not throw for.
  */
 var someNonCreateableEvents = [
+  "AnimationEvent",
   "AnimationPlaybackEvent",
   "AnimationPlayerEvent",
   "ApplicationCacheErrorEvent",
   "AudioProcessingEvent",
   "AutocompleteErrorEvent",
   "BeforeInstallPromptEvent",
   "BlobEvent",
   "ClipboardEvent",
+  "CloseEvent",
   "CommandEvent",
   "DataContainerEvent",
+  "ErrorEvent",
   "ExtendableEvent",
   "ExtendableMessageEvent",
   "FetchEvent",
   "FontFaceSetLoadEvent",
   "GamepadEvent",
   "GeofencingEvent",
+  "IDBVersionChangeEvent",
   "InstallEvent",
   "KeyEvent",
   "MIDIConnectionEvent",
   "MIDIMessageEvent",
   "MediaEncryptedEvent",
   "MediaKeyEvent",
   "MediaKeyMessageEvent",
   "MediaQueryListEvent",
@@ -99,17 +103,19 @@ var someNonCreateableEvents = [
   "MediaStreamTrackEvent",
   "MouseScrollEvent",
   "MutationEvent",
   "NotificationEvent",
   "NotifyPaintEvent",
   "OfflineAudioCompletionEvent",
   "OrientationEvent",
   "PageTransition", // Yes, with no "Event"
+  "PageTransitionEvent",
   "PointerEvent",
+  "PopStateEvent",
   "PopUpEvent",
   "PresentationConnectionAvailableEvent",
   "PresentationConnectionCloseEvent",
   "ProgressEvent",
   "PromiseRejectionEvent",
   "PushEvent",
   "RTCDTMFToneChangeEvent",
   "RTCDataChannelEvent",
@@ -123,18 +129,22 @@ var someNonCreateableEvents = [
   "ServicePortConnectEvent",
   "ServiceWorkerMessageEvent",
   "SimpleGestureEvent",
   "SpeechRecognitionError",
   "SpeechRecognitionEvent",
   "SpeechSynthesisEvent",
   "SyncEvent",
   "TimeEvent",
+  "TrackEvent",
+  "TransitionEvent",
+  "WebGLContextEvent",
   "WebKitAnimationEvent",
   "WebKitTransitionEvent",
+  "WheelEvent",
   "XULCommandEvent",
 ];
 someNonCreateableEvents.forEach(function (eventInterface) {
   // SVGEvents is allowed, but not SVGEvent.  Make sure we only test if it's
   // not whitelisted.
   if (!(eventInterface in aliases)) {
     test(function () {
       assert_throws("NOT_SUPPORTED_ERR", function () {

--- a/testing/web-platform/tests/dom/nodes/Document-createEvent.js
+++ b/testing/web-platform/tests/dom/nodes/Document-createEvent.js
@@ -1,33 +1,23 @@
 var aliases = {
-  "AnimationEvent": "AnimationEvent",
   "BeforeUnloadEvent": "BeforeUnloadEvent",
-  "CloseEvent": "CloseEvent",
   "CompositionEvent": "CompositionEvent",
   "CustomEvent": "CustomEvent",
   "DeviceMotionEvent": "DeviceMotionEvent",
   "DeviceOrientationEvent": "DeviceOrientationEvent",
   "DragEvent": "DragEvent",
-  "ErrorEvent": "ErrorEvent",
   "Event": "Event",
   "Events": "Event",
   "FocusEvent": "FocusEvent",
   "HashChangeEvent": "HashChangeEvent",
   "HTMLEvents": "Event",
-  "IDBVersionChangeEvent": "IDBVersionChangeEvent",
   "KeyboardEvent": "KeyboardEvent",
   "MessageEvent": "MessageEvent",
   "MouseEvent": "MouseEvent",
   "MouseEvents": "MouseEvent",
-  "PageTransitionEvent": "PageTransitionEvent",
-  "PopStateEvent": "PopStateEvent",
   "StorageEvent": "StorageEvent",
   "SVGEvents": "Event",
   "TextEvent": "CompositionEvent",
   "TouchEvent": "TouchEvent",
-  "TrackEvent": "TrackEvent",
-  "TransitionEvent": "TransitionEvent",
   "UIEvent": "UIEvent",
   "UIEvents": "UIEvent",
-  "WebGLContextEvent": "WebGLContextEvent",
-  "WheelEvent": "WheelEvent",
 };

--- a/testing/web-platform/tests/html/browsers/browsing-the-web/history-traversal/PopStateEvent.html
+++ b/testing/web-platform/tests/html/browsers/browsing-the-web/history-traversal/PopStateEvent.html
@@ -1,22 +1,16 @@
 <!doctype html>
 <meta charset=utf-8>
 <title>Synthetic popstate events</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
 <div id="log"></div>
 <script>
 test(function () {
-  var e = document.createEvent('PopStateEvent');
-  var eProto = Object.getPrototypeOf(e);
-  assert_equals(eProto, PopStateEvent.prototype);
-}, 'document.createEvent');
-
-test(function () {
   assert_false('initPopStateEvent' in PopStateEvent.prototype,
                'There should be no PopStateEvent#initPopStateEvent');
 }, 'initPopStateEvent');
 
 test(function () {
   var state = history.state;
   var data;
   window.addEventListener('popstate', function (e) {

--- a/testing/web-platform/tests/workers/Worker_dispatchEvent_ErrorEvent.htm
+++ b/testing/web-platform/tests/workers/Worker_dispatchEvent_ErrorEvent.htm
@@ -20,18 +20,12 @@ async_test(function(t) {
     assert_equals(e.colno, colno, 'colno');
     assert_equals(e.error, error, 'error');
   }), true);
   var e = new ErrorEvent(event, {bubbles:true, cancelable:true, message:message, filename:filename, lineno:lineno, colno:colno, error:error});
   worker.dispatchEvent(e);
 });
 
 test(function() {
-  var e = document.createEvent("ErrorEvent");
-  var eProto = Object.getPrototypeOf(e);
-  assert_equals(eProto, ErrorEvent.prototype);
-}, "document.createEvent('ErrorEvent')");
-
-test(function() {
   var e = new ErrorEvent("error");
   assert_false("initErrorEvent" in e, "should not be supported");
 }, "initErrorEvent");
 </script>