diff --git a/dom/base/nsGlobalWindow.cpp b/dom/base/nsGlobalWindow.cpp
index e21af85655..a9a387e15c 100644
--- a/dom/base/nsGlobalWindow.cpp
+++ b/dom/base/nsGlobalWindow.cpp
@@ -14625,21 +14625,6 @@ nsGlobalWindow::CreateImageBitmap(const ImageBitmapSource& aImage,
   return ImageBitmap::Create(this, aImage, Some(gfx::IntRect(aSx, aSy, aSw, aSh)), aRv);
 }
 
-already_AddRefed<mozilla::dom::Promise>
-nsGlobalWindow::CreateImageBitmap(const ImageBitmapSource& aImage,
-                                  int32_t aOffset, int32_t aLength,
-                                  ImageBitmapFormat aFormat,
-                                  const Sequence<ChannelPixelLayout>& aLayout,
-                                  ErrorResult& aRv)
-{
-  if (!ImageBitmap::ExtensionsEnabled(nullptr, nullptr)) {
-    aRv.Throw(NS_ERROR_TYPE_ERR);
-    return nullptr;
-  }
-  aRv.Throw(NS_ERROR_TYPE_ERR);
-  return nullptr;
-}
-
 // https://html.spec.whatwg.org/#structured-cloning
 void
 nsGlobalWindow::StructuredClone(JSContext* aCx,
diff --git a/dom/canvas/ImageBitmap.cpp b/dom/canvas/ImageBitmap.cpp
index e7bc1f08c8..c38f6d1650 100644
--- a/dom/canvas/ImageBitmap.cpp
+++ b/dom/canvas/ImageBitmap.cpp
@@ -1867,25 +1867,5 @@ ImageBitmap::MapDataInto(JSContext* aCx,
   return promise.forget();
 }
 
-/*static*/ already_AddRefed<Promise>
-ImageBitmap::Create(nsIGlobalObject* aGlobal,
-                    const ImageBitmapSource& aBuffer,
-                    int32_t aOffset, int32_t aLength,
-                    mozilla::dom::ImageBitmapFormat aFormat,
-                    const Sequence<ChannelPixelLayout>& aLayout,
-                    ErrorResult& aRv)
-{
-  MOZ_ASSERT(aGlobal);
-
-  RefPtr<Promise> promise = Promise::Create(aGlobal, aRv);
-
-  if (NS_WARN_IF(aRv.Failed())) {
-    return nullptr;
-  }
-
-  aRv.Throw(NS_ERROR_NOT_IMPLEMENTED);
-  return promise.forget();
-}
-
 } // namespace dom
 } // namespace mozilla
diff --git a/dom/canvas/ImageBitmap.h b/dom/canvas/ImageBitmap.h
index f677ad6642..20422d969c 100644
--- a/dom/canvas/ImageBitmap.h
+++ b/dom/canvas/ImageBitmap.h
@@ -132,14 +132,6 @@ public:
   Create(nsIGlobalObject* aGlobal, const ImageBitmapSource& aSrc,
          const Maybe<gfx::IntRect>& aCropRect, ErrorResult& aRv);
 
-  static already_AddRefed<Promise>
-  Create(nsIGlobalObject* aGlobal,
-         const ImageBitmapSource& aBuffer,
-         int32_t aOffset, int32_t aLength,
-         mozilla::dom::ImageBitmapFormat aFormat,
-         const Sequence<mozilla::dom::ChannelPixelLayout>& aLayout,
-         ErrorResult& aRv);
-
   static JSObject*
   ReadStructuredClone(JSContext* aCx,
                       JSStructuredCloneReader* aReader,
diff --git a/dom/webidl/WindowOrWorkerGlobalScope.webidl b/dom/webidl/WindowOrWorkerGlobalScope.webidl
index d378ba49ec..2989bc15c8 100644
--- a/dom/webidl/WindowOrWorkerGlobalScope.webidl
+++ b/dom/webidl/WindowOrWorkerGlobalScope.webidl
@@ -72,18 +72,3 @@ partial interface WindowOrWorkerGlobalScope {
   [Throws, Func="mozilla::dom::cache::CacheStorage::PrefEnabled", SameObject]
   readonly attribute CacheStorage caches;
 };
-
-// Mozilla extensions
-partial interface WindowOrWorkerGlobalScope {
-  // Extensions to ImageBitmap bits.
-  // Bug 1141979 - [FoxEye] Extend ImageBitmap with interfaces to access its
-  // underlying image data
-  //
-  // Note:
-  // Overloaded functions cannot have different "extended attributes",
-  // so I cannot add preference on the extended version of createImageBitmap().
-  // To work around, I will then check the preference at run time and throw if
-  // the preference is set to be false.
-  [Throws]
-  Promise<ImageBitmap> createImageBitmap(ImageBitmapSource aImage, long aOffset, long aLength, ImageBitmapFormat aFormat, ImagePixelLayout aLayout);
-};
diff --git a/dom/workers/WorkerScope.cpp b/dom/workers/WorkerScope.cpp
index 6a05dfaa08..714e437349 100644
--- a/dom/workers/WorkerScope.cpp
+++ b/dom/workers/WorkerScope.cpp
@@ -461,25 +461,6 @@ WorkerGlobalScope::CreateImageBitmap(const ImageBitmapSource& aImage,
   return ImageBitmap::Create(this, aImage, Some(gfx::IntRect(aSx, aSy, aSw, aSh)), aRv);
 }
 
-already_AddRefed<mozilla::dom::Promise>
-WorkerGlobalScope::CreateImageBitmap(const ImageBitmapSource& aImage,
-                                     int32_t aOffset, int32_t aLength,
-                                     ImageBitmapFormat aFormat,
-                                     const Sequence<ChannelPixelLayout>& aLayout,
-                                     ErrorResult& aRv)
-{
-  JSContext* cx = GetCurrentThreadJSContext();
-  MOZ_ASSERT(cx);
-
-  if (!ImageBitmap::ExtensionsEnabled(cx, nullptr)) {
-    aRv.Throw(NS_ERROR_TYPE_ERR);
-    return nullptr;
-  }
-
-  aRv.Throw(NS_ERROR_TYPE_ERR);
-  return nullptr;
-}
-
 // https://html.spec.whatwg.org/#structured-cloning
 void WorkerGlobalScope::StructuredClone(JSContext* aCx,
                                         JS::Handle<JS::Value> aValue,