Backed out changeset fe6d35a774ed (bug 1333901) for causing hazard warnings after landing

dom/events/EventDispatcher.cpp

@@ -26,7 +26,6 @@
 #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"
@@ -1165,13 +1164,6 @@ EventDispatcher::CreateEvent(EventTarget* aOwner,
     event->MarkUninitialized();
     return event.forget();
   }
-  if (aEventType.LowerCaseEqualsLiteral("errorevent")) {
-    LOG_EVENT_CREATION(ERROREVENT);
-    RefPtr<Event> event =
-      ErrorEvent::Constructor(aOwner, EmptyString(), ErrorEventInit());
-    event->MarkUninitialized();
-    return event.forget();
-  }
 
 #undef LOG_EVENT_CREATION
 

testing/web-platform/meta/workers/Worker_dispatchEvent_ErrorEvent.htm.ini

@@ -0,0 +1,5 @@
+[Worker_dispatchEvent_ErrorEvent.htm]
+  type: testharness
+  [document.createEvent('ErrorEvent')]
+    expected: FAIL
+

toolkit/components/telemetry/Histograms.json

@@ -282,13 +282,6 @@
     "kind": "count",
     "bug_numbers": [1295588, 1251198]
   },
-  "CREATE_EVENT_ERROREVENT" : {
-    "alert_emails": ["ayg@aryeh.name"],
-    "description": "Was document.createEvent(\"errorevent\") ever called",
-    "expires_in_version": "56",
-    "kind": "count",
-    "bug_numbers": [1295588, 1251198, 1333901]
-  },
   "CREATE_EVENT_EVENT" : {
     "alert_emails": ["ayg@aryeh.name"],
     "description": "Was document.createEvent(\"event\") ever called",