DOM: AbortController and AbortSignal

For whatwg/dom#437.

dom/abort/event.any.js

@@ -0,0 +1,22 @@
+test(t => {
+  const c = new AbortController(),
+        s = c.signal;
+  let state = "begin";
+
+  assert_false(s.aborted);
+
+  s.addEventListener("abort",
+    t.step_func(e => {
+      assert_equals(state, "begin");
+      state = "aborted";
+    })
+  );
+  c.abort();
+
+  assert_equals(state, "aborted");
+  assert_true(s.aborted);
+
+  c.abort();
+}, "AbortController() basics");
+
+done();

dom/interface-objects.html

@@ -15,6 +15,8 @@
   "Event",
   "CustomEvent",
   "EventTarget",
+  "AbortController",
+  "AbortSignal",
   "Node",
   "Document",
   "DOMImplementation",

dom/interfaces.html

@@ -24,6 +24,8 @@ <h1>DOM IDL tests</h1>
     EventTarget: ['new EventTarget()'],
     Event: ['document.createEvent("Event")', 'new Event("foo")'],
     CustomEvent: ['new CustomEvent("foo")'],
+    AbortController: ['new AbortController()'],
+    AbortSignal: ['new AbortController().signal'],
     Document: ['new Document()'],
     XMLDocument: ['xmlDoc'],
     DOMImplementation: ['document.implementation'],

interfaces/dom.idl

@@ -61,6 +61,23 @@ dictionary EventListenerOptions {
 };
 
 
+[Constructor,
+ Exposed=(Window,Worker)]
+interface AbortController {
+  [SameObject] readonly attribute AbortSignal signal;
+
+  void abort();
+};
+
+
+[Exposed=(Window,Worker)]
+interface AbortSignal : EventTarget {
+  readonly attribute boolean aborted;
+
+  attribute EventHandler onabort;
+};
+
+
 [NoInterfaceObject,
  Exposed=Window]
 interface NonElementParentNode {