Update the requestidlecallback IDL file

interfaces/requestidlecallback.idl

@@ -0,0 +1,22 @@
+// GENERATED CONTENT - DO NOT EDIT
+// Content of this file was automatically extracted from the
+// "Cooperative Scheduling of Background Tasks" spec.
+// See: https://w3c.github.io/requestidlecallback/
+
+partial interface Window {
+    unsigned long requestIdleCallback(IdleRequestCallback callback,
+                                      optional IdleRequestOptions options);
+    void          cancelIdleCallback(unsigned long handle);
+};
+
+dictionary IdleRequestOptions {
+    unsigned long timeout;
+};
+
+[Exposed=Window]
+interface IdleDeadline {
+    DOMHighResTimeStamp timeRemaining();
+    readonly attribute boolean didTimeout;
+};
+
+callback IdleRequestCallback = void (IdleDeadline deadline);

requestidlecallback/idlharness.window.js

@@ -0,0 +1,29 @@
+// META: script=/resources/WebIDLParser.js
+// META: script=/resources/idlharness.js
+
+async_test(function() {
+  const srcs = ['requestidlecallback', 'html', 'dom'];
+  Promise.all(srcs.map(i => fetch(`/interfaces/${i}.idl`).then(r => r.text())))
+    .then(([idl, html, dom]) => {
+      var idl_array = new IdlArray();
+      idl_array.add_idls(idl);
+      idl_array.add_dependency_idls(html);
+      idl_array.add_dependency_idls(dom);
+      idl_array.add_objects({Window: ['window']});
+
+      let deadline;
+      const execIDLTest = this.step_func_done(function() {
+        idl_array.add_objects({IdleDeadline: [deadline]});
+        idl_array.test();
+      });
+
+      if (!window.requestIdleCallback) {
+        execIDLTest();
+      } else {
+        requestIdleCallback(this.step_func(d => {
+          deadline = d;
+          execIDLTest();
+        }));
+      }
+    });
+}, 'IdleDeadline object setup');