Implemented Houdini worklets.

components/script/dom/webidls/Console.webidl

@@ -10,7 +10,7 @@
  */
 
 [ClassString="Console",
- Exposed=(Window,Worker),
+ Exposed=(Window,Worker,Worklet),
  ProtoObjectHack]
 namespace console {
   // These should be DOMString message, DOMString message2, ...

components/script/dom/webidls/EventTarget.webidl

@@ -5,7 +5,7 @@
  * https://dom.spec.whatwg.org/#interface-eventtarget
  */
 
-[Abstract, Exposed=(Window,Worker)]
+[Abstract, Exposed=(Window,Worker,Worklet)]
 interface EventTarget {
   void addEventListener(DOMString type,
                         EventListener? listener,

components/script/dom/webidls/GlobalScope.webidl

@@ -5,6 +5,6 @@
 // This interface is entirely internal to Servo, and should not be accessible to
 // web pages.
 
-[Exposed=(Window,Worker),
+[Exposed=(Window,Worker,Worklet),
  Inline]
 interface GlobalScope : EventTarget {};

components/script/dom/webidls/TestWorklet.webidl

@@ -0,0 +1,12 @@
+/* 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/. */
+
+// This interface is entirely internal to Servo, and should not be accessible to
+// web pages.
+
+[Pref="dom.worklet.testing.enabled", Exposed=(Window), Constructor]
+interface TestWorklet {
+   [NewObject] Promise<void> addModule(USVString moduleURL, optional WorkletOptions options);
+   DOMString? lookup(DOMString key);
+};

components/script/dom/webidls/TestWorkletGlobalScope.webidl

@@ -0,0 +1,11 @@
+/* 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/. */
+
+// This interface is entirely internal to Servo, and should not be accessible to
+// web pages.
+
+[Global=(Worklet,TestWorklet), Exposed=TestWorklet]
+interface TestWorkletGlobalScope : WorkletGlobalScope {
+    void registerKeyValue(DOMString key, DOMString value);
+};

components/script/dom/webidls/VoidFunction.webidl

@@ -0,0 +1,13 @@
+/* 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://heycam.github.io/webidl/#VoidFunction
+ *
+ * © Copyright 2004-2011 Apple Computer, Inc., Mozilla Foundation, and
+ * Opera Software ASA. You are granted a license to use, reproduce
+ * and create derivative works of this document.
+ */
+
+callback VoidFunction = void ();

components/script/dom/webidls/Window.webidl

@@ -201,3 +201,4 @@ partial interface Window {
    readonly attribute TestRunner testRunner;
    //readonly attribute EventSender eventSender;
 };
+

components/script/dom/webidls/Worklet.webidl

@@ -0,0 +1,13 @@
+/* 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/. */
+
+// https://drafts.css-houdini.org/worklets/#worklet
+[Exposed=(Window)]
+interface Worklet {
+    [NewObject] Promise<void> addModule(USVString moduleURL, optional WorkletOptions options);
+};
+
+dictionary WorkletOptions {
+    RequestCredentials credentials = "omit";
+};

components/script/dom/webidls/WorkletGlobalScope.webidl

@@ -0,0 +1,10 @@
+/* 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/. */
+
+// https://drafts.css-houdini.org/worklets/#workletglobalscope
+// TODO: The spec IDL doesn't make this a subclass of EventTarget
+//       https://github.com/whatwg/html/issues/2611
+[Exposed=Worklet]
+interface WorkletGlobalScope: GlobalScope {
+};