--- a/dom/canvas/ImageBitmap.cpp
+++ b/dom/canvas/ImageBitmap.cpp
@@ -1390,10 +1390,22 @@ ImageBitmap::WriteStructuredClone(JSStru
                                                  true);
   }
   MOZ_ASSERT(dstDataSurface);
   Factory::CopyDataSourceSurface(snapshot, dstDataSurface);
   aClonedSurfaces.AppendElement(dstDataSurface);
   return true;
 }
 
+/*static*/ bool
+ImageBitmap::ExtensionsEnabled(JSContext* aCx, JSObject*)
+{
+  if (NS_IsMainThread()) {
+    return Preferences::GetBool("canvas.imagebitmap_extensions.enabled");
+  } else {
+    WorkerPrivate* workerPrivate = GetWorkerPrivateFromContext(aCx);
+    MOZ_ASSERT(workerPrivate);
+    return workerPrivate->ImageBitmapExtensionsEnabled();
+  }
+}
+
 } // namespace dom
 } // namespace mozilla

--- a/dom/canvas/ImageBitmap.h
+++ b/dom/canvas/ImageBitmap.h
@@ -131,16 +131,19 @@ public:
                       const nsTArray<RefPtr<gfx::DataSourceSurface>>& aClonedSurfaces,
                       uint32_t aIndex);
 
   static bool
   WriteStructuredClone(JSStructuredCloneWriter* aWriter,
                        nsTArray<RefPtr<gfx::DataSourceSurface>>& aClonedSurfaces,
                        ImageBitmap* aImageBitmap);
 
+  // Mozilla Extensions
+  static bool ExtensionsEnabled(JSContext* aCx, JSObject* aObj);
+
   friend CreateImageBitmapFromBlob;
   friend CreateImageBitmapFromBlobTask;
   friend CreateImageBitmapFromBlobWorkerTask;
 
 protected:
 
   /*
    * The default value of aIsPremultipliedAlpha is TRUE because that the

--- a/dom/workers/WorkerPrefs.h
+++ b/dom/workers/WorkerPrefs.h
@@ -19,16 +19,17 @@
 //   WORKER_PREF("foo.bar", UpdaterFunction)
 //
 //   * First argument is the name of the pref.
 //   * The name of the function that updates the new value of a pref.
 
 #if !(defined(DEBUG) || defined(MOZ_ENABLE_JS_DUMP))
 WORKER_SIMPLE_PREF("browser.dom.window.dump.enabled", DumpEnabled, DUMP)
 #endif
+WORKER_SIMPLE_PREF("canvas.imagebitmap_extensions.enabled", ImageBitmapExtensionsEnabled, IMAGEBITMAP_EXTENSIONS_ENABLED)
 WORKER_SIMPLE_PREF("dom.caches.enabled", DOMCachesEnabled, DOM_CACHES)
 WORKER_SIMPLE_PREF("dom.caches.testing.enabled", DOMCachesTestingEnabled, DOM_CACHES_TESTING)
 WORKER_SIMPLE_PREF("dom.performance.enable_user_timing_logging", PerformanceLoggingEnabled, PERFORMANCE_LOGGING_ENABLED)
 WORKER_SIMPLE_PREF("dom.webnotifications.enabled", DOMWorkerNotificationEnabled, DOM_WORKERNOTIFICATION)
 WORKER_SIMPLE_PREF("dom.webnotifications.serviceworker.enabled", DOMServiceWorkerNotificationEnabled, DOM_SERVICEWORKERNOTIFICATION)
 WORKER_SIMPLE_PREF("dom.serviceWorkers.enabled", ServiceWorkersEnabled, SERVICEWORKERS_ENABLED)
 WORKER_SIMPLE_PREF("dom.serviceWorkers.testing.enabled", ServiceWorkersTestingEnabled, SERVICEWORKERS_TESTING_ENABLED)
 WORKER_SIMPLE_PREF("dom.serviceWorkers.openWindow.enabled", OpenWindowEnabled, OPEN_WINDOW_ENABLED)

--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -785,16 +785,23 @@ pref("ui.scrollToClick", 0);
 pref("canvas.focusring.enabled", true);
 pref("canvas.customfocusring.enabled", false);
 pref("canvas.hitregions.enabled", false);
 pref("canvas.filters.enabled", false);
 // Add support for canvas path objects
 pref("canvas.path.enabled", true);
 pref("canvas.capturestream.enabled", true);
 
+// Disable the ImageBitmap-extensions in the release build.
+#ifdef RELEASE_BUILD
+pref("canvas.imagebitmap_extensions.enabled", false);
+#else
+pref("canvas.imagebitmap_extensions.enabled", true);
+#endif
+
 // We want the ability to forcibly disable platform a11y, because
 // some non-a11y-related components attempt to bring it up.  See bug
 // 538530 for details about Windows; we have a pref here that allows it
 // to be disabled for performance and testing resons.
 // See bug 761589 for the crossplatform aspect.
 //
 // This pref is checked only once, and the browser needs a restart to
 // pick up any changes.