--- a/dom/tests/mochitest/general/test_interfaces.html
+++ b/dom/tests/mochitest/general/test_interfaces.html
@@ -1408,16 +1408,18 @@ var interfaceNamesInGlobalScope =
     {name: "VTTRegion", disabled: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WaveShaperNode",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLActiveInfo",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLBuffer",
 // IMPORTANT: Do not change this list without review from a DOM peer!
+    "WebGLContextEvent",
+// IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLFramebuffer",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLProgram",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     {name: "WebGLQuery", nightly: true},
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "WebGLRenderbuffer",
 // IMPORTANT: Do not change this list without review from a DOM peer!

new file mode 100644
--- /dev/null
+++ b/dom/webidl/WebGLContextEvent.webidl
@@ -0,0 +1,20 @@
+/* -*- 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
+ * https://www.khronos.org/registry/webgl/specs/latest/1.0/#fire-a-webgl-context-event
+ */
+
+[Constructor(DOMString type, optional WebGLContextEventInit eventInit),
+ Exposed=(Window,Worker),
+ Func="mozilla::dom::OffscreenCanvas::PrefEnabledOnWorkerThread"]
+interface WebGLContextEvent : Event {
+  readonly attribute DOMString statusMessage;
+};
+
+// EventInit is defined in the DOM4 specification.
+dictionary WebGLContextEventInit : EventInit {
+  DOMString statusMessage = "";
+};

--- a/dom/webidl/WebGLRenderingContext.webidl
+++ b/dom/webidl/WebGLRenderingContext.webidl
@@ -788,31 +788,21 @@ interface WebGLRenderingContext {
 
     void viewport(GLint x, GLint y, GLsizei width, GLsizei height);
 };
 
 // For OffscreenCanvas
 // Reference: https://wiki.whatwg.org/wiki/OffscreenCanvas
 [Exposed=(Window,Worker)]
 partial interface WebGLRenderingContext {
-  [Func="mozilla::dom::OffscreenCanvas::PrefEnabled"]
-  void commit();
+    [Func="mozilla::dom::OffscreenCanvas::PrefEnabled"]
+    void commit();
 };
 
-/*[Constructor(DOMString type, optional WebGLContextEventInit eventInit)]
-interface WebGLContextEvent : Event {
-    readonly attribute DOMString statusMessage;
-    };*/
-
-// EventInit is defined in the DOM4 specification.
-/*dictionary WebGLContextEventInit : EventInit {
-    DOMString statusMessage;
-    };*/
-
-
+////////////////////////////////////////
 // specific extension interfaces
 
 [NoInterfaceObject]
 interface WEBGL_compressed_texture_s3tc
 {
     const GLenum COMPRESSED_RGB_S3TC_DXT1_EXT  = 0x83F0;
     const GLenum COMPRESSED_RGBA_S3TC_DXT1_EXT = 0x83F1;
     const GLenum COMPRESSED_RGBA_S3TC_DXT3_EXT = 0x83F2;

--- a/dom/webidl/moz.build
+++ b/dom/webidl/moz.build
@@ -825,16 +825,17 @@ GENERATED_EVENTS_WEBIDL_FILES = [
     'TrackEvent.webidl',
     'TVCurrentChannelChangedEvent.webidl',
     'TVCurrentSourceChangedEvent.webidl',
     'TVEITBroadcastedEvent.webidl',
     'TVScanningStateChangedEvent.webidl',
     'UDPMessageEvent.webidl',
     'UserProximityEvent.webidl',
     'USSDReceivedEvent.webidl',
+    'WebGLContextEvent.webidl',
 ]
 
 if CONFIG['MOZ_WEBRTC']:
     GENERATED_EVENTS_WEBIDL_FILES += [
         'MediaStreamTrackEvent.webidl',
         'RTCDataChannelEvent.webidl',
         'RTCPeerConnectionIceEvent.webidl',
         'RTCTrackEvent.webidl',

--- a/dom/workers/test/test_worker_interfaces.js
+++ b/dom/workers/test/test_worker_interfaces.js
@@ -192,16 +192,18 @@ var interfaceNamesInGlobalScope =
     "URL",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     "URLSearchParams",
 // IMPORTANT: Do not change this list without review from a DOM peer!
     { name: "WebGLActiveInfo", disabled: true },
 // IMPORTANT: Do not change this list without review from a DOM peer!
     { name: "WebGLBuffer", disabled: true },
 // IMPORTANT: Do not change this list without review from a DOM peer!
+    { name: "WebGLContextEvent", disabled: true },
+// IMPORTANT: Do not change this list without review from a DOM peer!
     { name: "WebGLFramebuffer", disabled: true },
 // IMPORTANT: Do not change this list without review from a DOM peer!
     { name: "WebGLProgram", disabled: true },
 // IMPORTANT: Do not change this list without review from a DOM peer!
     { name: "WebGLRenderbuffer", disabled: true },
 // IMPORTANT: Do not change this list without review from a DOM peer!
     { name: "WebGLRenderingContext", disabled: true },
 // IMPORTANT: Do not change this list without review from a DOM peer!