--- a/content/media/webspeech/recognition/SpeechRecognition.cpp
+++ b/content/media/webspeech/recognition/SpeechRecognition.cpp
@@ -13,17 +13,17 @@
 #include "mozilla/dom/MediaStreamTrackBinding.h"
 #include "mozilla/MediaManager.h"
 #include "mozilla/Services.h"
 
 #include "AudioSegment.h"
 #include "endpointer.h"
 
 #include "GeneratedEvents.h"
-#include "nsIDOMSpeechRecognitionEvent.h"
+#include "mozilla/dom/SpeechRecognitionEvent.h"
 #include "nsIObserverService.h"
 #include "nsServiceManagerUtils.h"
 
 #include <algorithm>
 
 namespace mozilla {
 namespace dom {
 
@@ -462,30 +462,30 @@ SpeechRecognition::WaitForSpeechEnd(Spee
   }
 }
 
 void
 SpeechRecognition::NotifyFinalResult(SpeechEvent* aEvent)
 {
   ResetAndEnd();
 
-  nsCOMPtr<nsIDOMEvent> domEvent;
-  NS_NewDOMSpeechRecognitionEvent(getter_AddRefs(domEvent), nullptr, nullptr, nullptr);
+  SpeechRecognitionEventInit init;
+  init.mBubbles = true;
+  init.mCancelable = false;
+  // init.mResultIndex = 0;
+  init.mResults = aEvent->mRecognitionResultList;
+  init.mInterpretation = NS_LITERAL_STRING("NOT_IMPLEMENTED");
+  // init.mEmma = nullptr;
 
-  nsCOMPtr<nsIDOMSpeechRecognitionEvent> srEvent = do_QueryInterface(domEvent);
-  nsRefPtr<SpeechRecognitionResultList> rlist = aEvent->mRecognitionResultList;
-  nsCOMPtr<nsISupports> ilist = do_QueryInterface(rlist);
-  srEvent->InitSpeechRecognitionEvent(NS_LITERAL_STRING("result"),
-                                      true, false, 0, ilist,
-                                      NS_LITERAL_STRING("NOT_IMPLEMENTED"),
-                                      nullptr);
-  domEvent->SetTrusted(true);
+  nsRefPtr<SpeechRecognitionEvent> event =
+    SpeechRecognitionEvent::Constructor(this, NS_LITERAL_STRING("result"), init);
+  event->SetTrusted(true);
 
   bool defaultActionEnabled;
-  this->DispatchEvent(domEvent, &defaultActionEnabled);
+  this->DispatchEvent(event, &defaultActionEnabled);
 }
 
 void
 SpeechRecognition::DoNothing(SpeechEvent* aEvent)
 {
 }
 
 void

--- a/content/media/webspeech/recognition/moz.build
+++ b/content/media/webspeech/recognition/moz.build
@@ -1,17 +1,16 @@
 # vim: set filetype=python:
 # 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/.
 
 XPIDL_MODULE = 'dom_webspeechrecognition'
 
 XPIDL_SOURCES = [
-  'nsIDOMSpeechRecognitionEvent.idl',
   'nsISpeechRecognitionService.idl'
 ]
 
 TEST_DIRS += ['test']
 
 EXPORTS.mozilla.dom += [
     'SpeechGrammar.h',
     'SpeechGrammarList.h',

deleted file mode 100644
--- a/content/media/webspeech/recognition/nsIDOMSpeechRecognitionEvent.idl
+++ /dev/null
@@ -1,31 +0,0 @@
-/* -*- Mode: IDL; 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/.
- *
- * The origin of this IDL file is
- * http://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html
- *
- * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
- * liability, trademark and document use rules apply.
- */
-
-#include "nsIDOMEvent.idl"
-
-interface SpeechRecognitionResultList;
-
-[builtinclass, uuid(98dded70-33af-42d5-819d-e15b6f4a3aba)]
-interface nsIDOMSpeechRecognitionEvent : nsIDOMEvent {
-    [noscript] void initSpeechRecognitionEvent(in DOMString eventTypeArg,
-                                               in boolean canBubbleArg,
-                                               in boolean cancelableArg,
-                                               in unsigned long resultIndex,
-                                               in nsISupports results,
-                                               in DOMString interpretation,
-                                               in nsIDOMDocument emma);
-
-    readonly attribute unsigned long resultIndex;
-    readonly attribute nsISupports results;
-    readonly attribute DOMString interpretation;
-    readonly attribute nsIDOMDocument emma;
-};

--- a/content/media/webspeech/synth/SpeechSynthesisUtterance.cpp
+++ b/content/media/webspeech/synth/SpeechSynthesisUtterance.cpp
@@ -3,19 +3,17 @@
 /* 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 "nsCOMPtr.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsGkAtoms.h"
 
-#include "GeneratedEvents.h"
-#include "nsIDOMSpeechSynthesisEvent.h"
-
+#include "mozilla/dom/SpeechSynthesisEvent.h"
 #include "mozilla/dom/SpeechSynthesisUtteranceBinding.h"
 #include "SpeechSynthesisUtterance.h"
 #include "SpeechSynthesisVoice.h"
 
 namespace mozilla {
 namespace dom {
 
 NS_IMPL_CYCLE_COLLECTION_INHERITED(SpeechSynthesisUtterance,
@@ -152,20 +150,22 @@ SpeechSynthesisUtterance::SetPitch(float
 }
 
 void
 SpeechSynthesisUtterance::DispatchSpeechSynthesisEvent(const nsAString& aEventType,
                                                        uint32_t aCharIndex,
                                                        float aElapsedTime,
                                                        const nsAString& aName)
 {
-  nsCOMPtr<nsIDOMEvent> domEvent;
-  NS_NewDOMSpeechSynthesisEvent(getter_AddRefs(domEvent), nullptr, nullptr, nullptr);
+  SpeechSynthesisEventInit init;
+  init.mBubbles = false;
+  init.mCancelable = false;
+  init.mCharIndex = aCharIndex;
+  init.mElapsedTime = aElapsedTime;
+  init.mName = aName;
 
-  nsCOMPtr<nsIDOMSpeechSynthesisEvent> ssEvent = do_QueryInterface(domEvent);
-  ssEvent->InitSpeechSynthesisEvent(aEventType, false, false,
-                                    aCharIndex, aElapsedTime, aName);
-
-  DispatchTrustedEvent(domEvent);
+  nsRefPtr<SpeechSynthesisEvent> event =
+    SpeechSynthesisEvent::Constructor(this, aEventType, init);
+  DispatchTrustedEvent(event);
 }
 
 } // namespace dom
 } // namespace mozilla

--- a/content/media/webspeech/synth/moz.build
+++ b/content/media/webspeech/synth/moz.build
@@ -5,17 +5,16 @@
 
 if CONFIG['MOZ_WEBSPEECH']:
 
     TEST_DIRS += ['test', 'ipc/test']
 
     XPIDL_MODULE = 'dom_webspeechsynth'
 
     XPIDL_SOURCES += [
-        'nsIDOMSpeechSynthesisEvent.idl',
         'nsISpeechService.idl',
         'nsISynthVoiceRegistry.idl'
     ]
 
     EXPORTS.mozilla.dom += [
         'ipc/SpeechSynthesisChild.h',
         'ipc/SpeechSynthesisParent.h',
         'nsSpeechTask.h',

deleted file mode 100644
--- a/content/media/webspeech/synth/nsIDOMSpeechSynthesisEvent.idl
+++ /dev/null
@@ -1,27 +0,0 @@
-/* -*- Mode: IDL; 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/.
- *
- * The origin of this IDL file is
- * http://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html
- *
- * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
- * liability, trademark and document use rules apply.
- */
-
-#include "nsIDOMEvent.idl"
-
-[uuid(b5240841-dc69-43dd-bcf1-9306b8ddaa09)]
-interface nsIDOMSpeechSynthesisEvent : nsIDOMEvent {
-  [noscript] void initSpeechSynthesisEvent(in DOMString aEventTypeArg,
-                                           in boolean aCanBubbleArg,
-                                           in boolean aCancelableArg,
-                                           in unsigned long aCharIndex,
-                                           in float aElapsedTime,
-                                           in DOMString aName);
-
-  readonly attribute unsigned long charIndex;
-  readonly attribute float elapsedTime;
-  readonly attribute DOMString name;
-};

--- a/dom/webidl/SpeechRecognitionEvent.webidl
+++ b/dom/webidl/SpeechRecognitionEvent.webidl
@@ -1,18 +1,17 @@
 /* -*- Mode: IDL; 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/.
  */
 interface nsISupports;
 
 [Pref="media.webspeech.recognition.enable",
- Constructor(DOMString type, optional SpeechRecognitionEventInit eventInitDict),
- HeaderFile="GeneratedEventClasses.h"]
+ Constructor(DOMString type, optional SpeechRecognitionEventInit eventInitDict)]
 interface SpeechRecognitionEvent : Event
 {
   readonly attribute unsigned long resultIndex;
   readonly attribute nsISupports? results;
   readonly attribute DOMString? interpretation;
   readonly attribute Document? emma;
 };
 

--- a/dom/webidl/SpeechSynthesisEvent.webidl
+++ b/dom/webidl/SpeechSynthesisEvent.webidl
@@ -6,17 +6,16 @@
  * The origin of this IDL file is
  * http://dvcs.w3.org/hg/speech-api/raw-file/tip/speechapi.html
  *
  * Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C
  * liability, trademark and document use rules apply.
  */
 
 [Constructor(DOMString type, optional SpeechSynthesisEventInit eventInitDict),
- HeaderFile="GeneratedEventClasses.h",
  Pref="media.webspeech.synth.enabled"]
 interface SpeechSynthesisEvent : Event
 {
   readonly attribute unsigned long charIndex;
   readonly attribute float elapsedTime;
   readonly attribute DOMString? name;
 };
 

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -511,16 +511,18 @@ if CONFIG['MOZ_WEBRTC']:
     ]
 
 if CONFIG['MOZ_WEBSPEECH']:
     WEBIDL_FILES += [
         'SpeechGrammar.webidl',
         'SpeechGrammarList.webidl',
         'SpeechRecognition.webidl',
         'SpeechRecognitionAlternative.webidl',
+        'SpeechRecognitionError.webidl',
+        'SpeechRecognitionEvent.webidl',
         'SpeechRecognitionResult.webidl',
         'SpeechRecognitionResultList.webidl',
         'SpeechSynthesis.webidl',
         'SpeechSynthesisEvent.webidl',
         'SpeechSynthesisUtterance.webidl',
         'SpeechSynthesisVoice.webidl',
     ]
 
@@ -602,22 +604,16 @@ if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'gonk
         'MozWifiManager.webidl',
         'MozWifiP2pManager.webidl',
     ]
 else:
     WEBIDL_FILES += [
         'InstallTrigger.webidl',
     ]
 
-if CONFIG['MOZ_WEBSPEECH']:
-    WEBIDL_FILES += [
-        'SpeechRecognitionError.webidl',
-        'SpeechRecognitionEvent.webidl',
-    ]
-
 if CONFIG['MOZ_B2G_FM']:
     WEBIDL_FILES += [
         'FMRadio.webidl',
     ]
 
 if not CONFIG['MOZ_DISABLE_CRYPTOLEGACY']:
     WEBIDL_FILES += [
         'CRMFObject.webidl',
@@ -662,16 +658,22 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'RTCPeerConnectionIdentityErrorEvent.webidl',
     'RTCPeerConnectionIdentityEvent.webidl',
     'SmartCardEvent.webidl',
     'TrackEvent.webidl',
     'UserProximityEvent.webidl',
     'USSDReceivedEvent.webidl',
 ]
 
+if CONFIG['MOZ_WEBSPEECH']:
+    GENERATED_EVENTS_WEBIDL_FILES += [
+        'SpeechRecognitionEvent.webidl',
+        'SpeechSynthesisEvent.webidl',
+    ]
+
 if CONFIG['MOZ_GAMEPAD']:
     GENERATED_EVENTS_WEBIDL_FILES += [
         'GamepadAxisMoveEvent.webidl',
         'GamepadButtonEvent.webidl',
         'GamepadEvent.webidl',
     ]
 
 if CONFIG['MOZ_B2G_BT']:

--- a/js/xpconnect/src/event_impl_gen.conf.in
+++ b/js/xpconnect/src/event_impl_gen.conf.in
@@ -7,22 +7,16 @@
  and should be in nsIDOM<name>.idl file and which should have
  <name>Init dictionary for the event constructor. """
 
 simple_events = [
     'CustomEvent',
     'StyleRuleChangeEvent',
     'StyleSheetChangeEvent',
     'StyleSheetApplicableStateChangeEvent',
-#ifdef MOZ_WEBSPEECH
-    'SpeechSynthesisEvent',
-#endif
-#ifdef MOZ_WEBSPEECH
-    'SpeechRecognitionEvent',
-#endif
   ]
 
 """ include file names """
 special_includes = [
     'nsContentUtils.h',
     'nsIDOMApplicationRegistry.h',
     'nsIDOMFile.h'
   ]

--- a/xpcom/reflect/xptinfo/ShimInterfaceInfo.cpp
+++ b/xpcom/reflect/xptinfo/ShimInterfaceInfo.cpp
@@ -119,20 +119,16 @@
 #include "nsIDOMParser.h"
 #include "nsIDOMProcessingInstruction.h"
 #include "nsIDOMRange.h"
 #include "nsIDOMRect.h"
 #include "nsIDOMScreen.h"
 #include "nsIDOMScrollAreaEvent.h"
 #include "nsIDOMSerializer.h"
 #include "nsIDOMSimpleGestureEvent.h"
-#ifdef MOZ_WEBSPEECH
-#include "nsIDOMSpeechRecognitionEvent.h"
-#include "nsIDOMSpeechSynthesisEvent.h"
-#endif // MOZ_WEBSPEECH
 #include "nsIDOMStyleSheet.h"
 #include "nsIDOMStyleSheetList.h"
 #include "nsIDOMStyleRuleChangeEvent.h"
 #include "nsIDOMStyleSheetApplicableStateChangeEvent.h"
 #include "nsIDOMStyleSheetChangeEvent.h"
 #include "nsIDOMSVGElement.h"
 #include "nsIDOMSVGLength.h"
 #include "nsIDOMText.h"
@@ -266,20 +262,16 @@
 #include "mozilla/dom/PositionErrorBinding.h"
 #include "mozilla/dom/ProcessingInstructionBinding.h"
 #include "mozilla/dom/RangeBinding.h"
 #include "mozilla/dom/RectBinding.h"
 #include "mozilla/dom/ScreenBinding.h"
 #include "mozilla/dom/SelectionBinding.h"
 #include "mozilla/dom/ScrollAreaEventBinding.h"
 #include "mozilla/dom/SimpleGestureEventBinding.h"
-#ifdef MOZ_WEBSPEECH
-#include "mozilla/dom/SpeechRecognitionEventBinding.h"
-#include "mozilla/dom/SpeechSynthesisEventBinding.h"
-#endif // MOZ_WEBSPEECH
 #include "mozilla/dom/StorageEventBinding.h"
 #include "mozilla/dom/StyleSheetBinding.h"
 #include "mozilla/dom/StyleSheetListBinding.h"
 #include "mozilla/dom/StyleRuleChangeEventBinding.h"
 #include "mozilla/dom/StyleSheetApplicableStateChangeEventBinding.h"
 #include "mozilla/dom/StyleSheetChangeEventBinding.h"
 #include "mozilla/dom/SVGElementBinding.h"
 #include "mozilla/dom/SVGLengthBinding.h"
@@ -464,20 +456,16 @@ const ComponentsInterfaceShimEntry kComp
   DEFINE_SHIM_WITH_CUSTOM_INTERFACE(nsIDOMParser, DOMParser),
   DEFINE_SHIM(ProcessingInstruction),
   DEFINE_SHIM(Range),
   DEFINE_SHIM(Rect),
   DEFINE_SHIM(Screen),
   DEFINE_SHIM(ScrollAreaEvent),
   DEFINE_SHIM_WITH_CUSTOM_INTERFACE(nsIDOMSerializer, XMLSerializer),
   DEFINE_SHIM(SimpleGestureEvent),
-#ifdef MOZ_WEBSPEECH
-  DEFINE_SHIM(SpeechRecognitionEvent),
-  DEFINE_SHIM(SpeechSynthesisEvent),
-#endif // MOZ_WEBSPEECH
   DEFINE_SHIM(StyleSheet),
   DEFINE_SHIM(StyleSheetList),
   DEFINE_SHIM(StyleRuleChangeEvent),
   DEFINE_SHIM(StyleSheetApplicableStateChangeEvent),
   DEFINE_SHIM(StyleSheetChangeEvent),
   DEFINE_SHIM(SVGElement),
   DEFINE_SHIM(SVGLength),
   DEFINE_SHIM(Text),