--- a/content/events/src/Makefile.in
+++ b/content/events/src/Makefile.in
@@ -55,17 +55,16 @@ CPPSRCS		= \
 		nsDOMNotifyPaintEvent.cpp \
 		nsDOMNotifyAudioAvailableEvent.cpp \
 		nsDOMSimpleGestureEvent.cpp \
 		nsDOMMozTouchEvent.cpp \
 		nsDOMEventTargetHelper.cpp \
 		nsDOMScrollAreaEvent.cpp \
 		nsDOMTransitionEvent.cpp \
 		nsDOMAnimationEvent.cpp \
-		nsDOMSettingsEvent.cpp \
 		nsDOMTouchEvent.cpp \
 		nsDOMCompositionEvent.cpp \
 		$(NULL)
 
 ifdef MOZ_B2G_RIL
 CPPSRCS += \
     nsDOMWifiEvent.cpp \
     $(NULL)

deleted file mode 100644
--- a/content/events/src/nsDOMSettingsEvent.cpp
+++ /dev/null
@@ -1,77 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "nsDOMClassInfoID.h"
-#include "nsDOMSettingsEvent.h"
-#include "DictionaryHelpers.h"
-
-NS_IMPL_CYCLE_COLLECTION_CLASS(nsDOMMozSettingsEvent)
-
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(nsDOMMozSettingsEvent, nsDOMEvent)
-  NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMPTR(mSettingValue)
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
-
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(nsDOMMozSettingsEvent, nsDOMEvent)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mSettingValue)
-NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
-
-DOMCI_DATA(MozSettingsEvent, nsDOMMozSettingsEvent)
-
-NS_INTERFACE_MAP_BEGIN(nsDOMMozSettingsEvent)
-  NS_INTERFACE_MAP_ENTRY(nsIDOMMozSettingsEvent)
-  NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(MozSettingsEvent)
-NS_INTERFACE_MAP_END_INHERITING(nsDOMEvent)
-
-NS_IMPL_ADDREF_INHERITED(nsDOMMozSettingsEvent, nsDOMEvent)
-NS_IMPL_RELEASE_INHERITED(nsDOMMozSettingsEvent, nsDOMEvent)
-
-NS_IMETHODIMP
-nsDOMMozSettingsEvent::GetSettingName(nsAString & aSettingName)
-{
-  aSettingName = mSettingName;
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsDOMMozSettingsEvent::GetSettingValue(nsIVariant** aSettingValue)
-{
-  NS_IF_ADDREF(*aSettingValue = mSettingValue);
-  return NS_OK;
-}
-
-NS_IMETHODIMP
-nsDOMMozSettingsEvent::InitMozSettingsEvent(const nsAString& aType,
-                                            bool aCanBubble,
-                                            bool aCancelable,
-                                            const nsAString &aSettingName,
-                                            nsIVariant *aSettingValue)
-{
-  nsresult rv = nsDOMEvent::InitEvent(aType, aCanBubble, aCancelable);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  mSettingName = aSettingName;
-  mSettingValue = aSettingValue;
-
-  return NS_OK;
-}
-
-nsresult
-nsDOMMozSettingsEvent::InitFromCtor(const nsAString& aType,
-                                    JSContext* aCx, jsval* aVal)
-{
-  mozilla::dom::MozSettingsEventInit d;
-  nsresult rv = d.Init(aCx, aVal);
-  NS_ENSURE_SUCCESS(rv, rv);
-  return InitMozSettingsEvent(aType, d.bubbles, d.cancelable, d.settingName, d.settingValue);
-}
-
-nsresult
-NS_NewDOMMozSettingsEvent(nsIDOMEvent** aInstancePtrResult,
-                          nsPresContext* aPresContext,
-                          nsEvent* aEvent) 
-{
-  nsDOMMozSettingsEvent* e = new nsDOMMozSettingsEvent(aPresContext, aEvent);
-  return CallQueryInterface(e, aInstancePtrResult);
-}

deleted file mode 100644
--- a/content/events/src/nsDOMSettingsEvent.h
+++ /dev/null
@@ -1,33 +0,0 @@
-/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this file,
- * You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef nsDOMSettingsEvent_h__
-#define nsDOMSettingsEvent_h__
-
-#include "nsIDOMSettingsManager.h"
-#include "nsDOMEvent.h"
-
-class nsDOMMozSettingsEvent : public nsDOMEvent,
-                              public nsIDOMMozSettingsEvent
-{
-public:
-  nsDOMMozSettingsEvent(nsPresContext* aPresContext, nsEvent* aEvent)
-    : nsDOMEvent(aPresContext, aEvent) {}
-                     
-  NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsDOMMozSettingsEvent, nsDOMEvent)
-  // Forward to base class
-  NS_FORWARD_TO_NSDOMEVENT
-
-  NS_DECL_NSIDOMMOZSETTINGSEVENT
-
-  virtual nsresult InitFromCtor(const nsAString& aType,
-                                JSContext* aCx, jsval* aVal);
-private:
-  nsString mSettingName;
-  nsCOMPtr<nsIVariant> mSettingValue;
-};
-
-#endif // nsDOMSettingsEvent_h__

--- a/dom/base/nsDOMClassInfo.cpp
+++ b/dom/base/nsDOMClassInfo.cpp
@@ -1637,18 +1637,16 @@ static nsDOMClassInfoData sClassInfoData
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
   NS_DEFINE_CLASSINFO_DATA(MediaQueryList, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(MutationObserver, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(MutationRecord, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
-  NS_DEFINE_CLASSINFO_DATA(MozSettingsEvent, nsDOMGenericSH,
-                           DOM_DEFAULT_SCRIPTABLE_FLAGS)
 
 #ifdef MOZ_B2G_RIL
   NS_DEFINE_CLASSINFO_DATA(MozWifiStatusChangeEvent, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(MozWifiConnectionInfoEvent, nsDOMGenericSH,
                            DOM_DEFAULT_SCRIPTABLE_FLAGS)
   NS_DEFINE_CLASSINFO_DATA(Telephony, nsEventTargetSH,
                            EVENTTARGET_SCRIPTABLE_FLAGS)
@@ -1732,17 +1730,16 @@ static const nsContractIDMapData kConstr
   {                                                         \
     nsIDOMEvent* e = nullptr;                                \
     nsresult rv = NS_NewDOM##_class(&e, nullptr, nullptr);    \
     *aInstancePtrResult = e;                                \
     return rv;                                              \
   }
 
 NS_DEFINE_EVENT_CTOR(Event)
-NS_DEFINE_EVENT_CTOR(MozSettingsEvent)
 NS_DEFINE_EVENT_CTOR(UIEvent)
 NS_DEFINE_EVENT_CTOR(MouseEvent)
 #ifdef MOZ_B2G_RIL
 NS_DEFINE_EVENT_CTOR(MozWifiStatusChangeEvent)
 NS_DEFINE_EVENT_CTOR(MozWifiConnectionInfoEvent)
 #endif
 
 #define MOZ_GENERATED_EVENT_LIST
@@ -1778,17 +1775,16 @@ struct nsConstructorFuncMapData
   { eDOMClassInfo_##_class##_id, NS_DOM##_class##Ctor },
 
 static const nsConstructorFuncMapData kConstructorFuncMap[] =
 {
   NS_DEFINE_CONSTRUCTOR_FUNC_DATA(Blob, nsDOMMultipartFile::NewBlob)
   NS_DEFINE_CONSTRUCTOR_FUNC_DATA(File, nsDOMFileFile::NewFile)
   NS_DEFINE_CONSTRUCTOR_FUNC_DATA(MozBlobBuilder, NS_NewBlobBuilder)
   NS_DEFINE_EVENT_CONSTRUCTOR_FUNC_DATA(Event)
-  NS_DEFINE_EVENT_CONSTRUCTOR_FUNC_DATA(MozSettingsEvent)
   NS_DEFINE_EVENT_CONSTRUCTOR_FUNC_DATA(UIEvent)
   NS_DEFINE_EVENT_CONSTRUCTOR_FUNC_DATA(MouseEvent)
   NS_DEFINE_EVENT_CONSTRUCTOR_FUNC_DATA(StorageEvent)
 #ifdef MOZ_B2G_RIL
   NS_DEFINE_EVENT_CONSTRUCTOR_FUNC_DATA(MozWifiStatusChangeEvent)
   NS_DEFINE_EVENT_CONSTRUCTOR_FUNC_DATA(MozWifiConnectionInfoEvent)
 #endif
 #define MOZ_GENERATED_EVENT_LIST
@@ -4406,21 +4402,16 @@ nsDOMClassInfo::Init()
   DOM_CLASSINFO_MAP_BEGIN(MutationObserver, nsIDOMMutationObserver)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMMutationObserver)
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN(MutationRecord, nsIDOMMutationRecord)
     DOM_CLASSINFO_MAP_ENTRY(nsIDOMMutationRecord)
   DOM_CLASSINFO_MAP_END
 
-  DOM_CLASSINFO_MAP_BEGIN(MozSettingsEvent, nsIDOMMozSettingsEvent)
-     DOM_CLASSINFO_MAP_ENTRY(nsIDOMMozSettingsEvent)
-     DOM_CLASSINFO_EVENT_MAP_ENTRIES
-  DOM_CLASSINFO_MAP_END
-
 #ifdef MOZ_B2G_RIL
   DOM_CLASSINFO_MAP_BEGIN(MozWifiStatusChangeEvent, nsIDOMMozWifiStatusChangeEvent)
      DOM_CLASSINFO_MAP_ENTRY(nsIDOMMozWifiStatusChangeEvent)
      DOM_CLASSINFO_EVENT_MAP_ENTRIES
   DOM_CLASSINFO_MAP_END
 
   DOM_CLASSINFO_MAP_BEGIN(MozWifiConnectionInfoEvent, nsIDOMMozWifiConnectionInfoEvent)
      DOM_CLASSINFO_MAP_ENTRY(nsIDOMMozWifiConnectionInfoEvent)

--- a/dom/base/nsDOMClassInfoClasses.h
+++ b/dom/base/nsDOMClassInfoClasses.h
@@ -502,18 +502,16 @@ DOMCI_CLASS(TouchEvent)
 DOMCI_CLASS(MozCSSKeyframeRule)
 DOMCI_CLASS(MozCSSKeyframesRule)
 
 DOMCI_CLASS(MediaQueryList)
 
 DOMCI_CLASS(MutationObserver)
 DOMCI_CLASS(MutationRecord)
 
-DOMCI_CLASS(MozSettingsEvent)
-
 #ifdef MOZ_B2G_RIL
 DOMCI_CLASS(MozWifiStatusChangeEvent)
 DOMCI_CLASS(MozWifiConnectionInfoEvent)
 DOMCI_CLASS(Telephony)
 DOMCI_CLASS(TelephonyCall)
 DOMCI_CLASS(CallEvent)
 DOMCI_CLASS(MozVoicemail)
 DOMCI_CLASS(MozVoicemailEvent)

--- a/dom/interfaces/settings/Makefile.in
+++ b/dom/interfaces/settings/Makefile.in
@@ -11,11 +11,12 @@ include $(DEPTH)/config/autoconf.mk
 
 MODULE         = dom
 XPIDL_MODULE   = dom_settings
 GRE_MODULE     = 1
 
 XPIDLSRCS =                           \
             nsIDOMSettingsManager.idl \
             nsISettingsService.idl    \
+            nsIDOMMozSettingsEvent.idl \
             $(NULL)
 
 include $(topsrcdir)/config/rules.mk

new file mode 100644
--- /dev/null
+++ b/dom/interfaces/settings/nsIDOMMozSettingsEvent.idl
@@ -0,0 +1,25 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIDOMEvent.idl"
+interface nsIVariant;
+
+[scriptable, builtinclass, uuid(5e304193-af49-4546-8329-bf7c9159ed98)]
+interface nsIDOMMozSettingsEvent : nsIDOMEvent
+{
+  readonly attribute DOMString  settingName;
+  readonly attribute nsIVariant settingValue;
+
+  [noscript] void initMozSettingsEvent(in DOMString aType,
+                                       in boolean aCanBubble,
+                                       in boolean aCancelable,
+                                       in DOMString aSettingName,
+                                       in nsIVariant aSettingValue);
+};
+
+dictionary MozSettingsEventInit : EventInit
+{
+  DOMString  settingName;
+  nsIVariant settingValue;
+};

--- a/dom/interfaces/settings/nsIDOMSettingsManager.idl
+++ b/dom/interfaces/settings/nsIDOMSettingsManager.idl
@@ -1,15 +1,14 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
  * You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "domstubs.idl"
 #include "nsIDOMEventTarget.idl"
-#include "nsIDOMEvent.idl"
 
 interface nsIDOMDOMRequest;
 interface nsIVariant;
 
 [scriptable, uuid(ef95ddd0-6308-11e1-b86c-0800200c9a66)]
 interface nsIDOMSettingsLock : nsISupports
 {
   // Contains a JSON object with name/value pairs to be set.
@@ -26,27 +25,8 @@ interface nsIDOMSettingsManager : nsISup
 {
   nsIDOMSettingsLock getLock();
 
   void addObserver(in DOMString name, in jsval callback);
   void removeObserver(in DOMString name, in jsval callback);
 
   attribute nsIDOMEventListener onsettingchange;
 };
-
-[scriptable, builtinclass, uuid(5e304193-af49-4546-8329-bf7c9159ed98)]
-interface nsIDOMMozSettingsEvent : nsIDOMEvent
-{
-  readonly attribute DOMString  settingName;
-  readonly attribute nsIVariant settingValue;
-
-  [noscript] void initMozSettingsEvent(in DOMString aType,
-                                       in boolean aCanBubble,
-                                       in boolean aCancelable,
-                                       in DOMString aSettingName,
-                                       in nsIVariant aSettingValue);
-};
-
-dictionary MozSettingsEventInit : EventInit
-{
-  DOMString  settingName;
-  nsIVariant settingValue;
-};

--- a/js/xpconnect/src/dictionary_helper_gen.conf
+++ b/js/xpconnect/src/dictionary_helper_gen.conf
@@ -7,17 +7,16 @@ dictionaries = [
      [ 'EventInit', 'nsIDOMEvent.idl' ],
      [ 'UIEventInit', 'nsIDOMUIEvent.idl' ],
      [ 'MouseEventInit', 'nsIDOMMouseEvent.idl' ],
      [ 'IDBObjectStoreParameters', 'nsIIDBDatabase.idl' ],
      [ 'IDBIndexParameters', 'nsIIDBObjectStore.idl' ],
      [ 'StorageEventInit', 'nsIDOMStorageEvent.idl' ],
      [ 'BlobPropertyBag', 'nsIDOMFile.idl' ],
      [ 'MutationObserverInit', 'nsIDOMMutationObserver.idl' ],
-     [ 'SettingsEventInit', 'nsIDOMSettingsManager.idl' ],
      [ 'WifiConnectionInfoEventInit', 'nsIWifiEventInits.idl' ],
      [ 'WifiStatusChangeEventInit', 'nsIWifiEventInits.idl' ],
      [ 'GeoPositionOptions', 'nsIDOMGeoGeolocation.idl' ],
      [ 'DOMFileMetadataParameters', 'nsIDOMLockedFile.idl' ],
      [ 'XMLHttpRequestParameters', 'nsIXMLHttpRequest.idl' ],
      [ 'DeviceStorageEnumerationParameters', 'nsIDOMDeviceStorage.idl' ],
      [ 'CameraSize', 'nsIDOMCameraManager.idl' ],
      [ 'CameraRegion', 'nsIDOMCameraManager.idl' ],

--- a/js/xpconnect/src/event_impl_gen.conf.in
+++ b/js/xpconnect/src/event_impl_gen.conf.in
@@ -4,16 +4,17 @@
  file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
  The name of the event which real interface should have nsIDOM-prefix,
  and should be in nsIDOM<name>.idl file and which should have
  <name>Init dictionary for the event constructor. """
 
 simple_events = [
     'DeviceProximityEvent',
+    'MozSettingsEvent',
     'UserProximityEvent',
     'CustomEvent',
     'PageTransitionEvent',
     'PopStateEvent',
     'HashChangeEvent',
     'CloseEvent',
     'MozContactChangeEvent',
     'DeviceOrientationEvent',