WIP don't review: Implement Future

Source/core/dom/Future.idl

Index: Source/core/dom/Future.idl
diff --git a/Source/modules/webmidi/MIDIInput.idl b/Source/core/dom/Future.idl
similarity index 73%
copy from Source/modules/webmidi/MIDIInput.idl
copy to Source/core/dom/Future.idl
index 8c0ae3cd90aad230083403867cef594a190a0674..0222930ede8fa667431bca575efe8fe2004f4331 100644
--- a/Source/modules/webmidi/MIDIInput.idl
+++ b/Source/core/dom/Future.idl
@@ -29,9 +29,18 @@
  */
 
 [
-    NoInterfaceObject,
     ActiveDOMObject,
-    EventTarget
-] interface MIDIInput : MIDIPort {
-    attribute EventListener onmidimessage;
+    CustomConstructor(FutureInit init)
+] interface Future {
+    static Future accept(any value);
+    static Future resolve(any value); // same as any(value)
+    static Future reject(any value);
+
+    static Future anyof(any... values); // exposed as "any" in JavaScript, without "_"
+    static Future every(any... values);
+    static Future some(any... values);
+
+    [Custom] Future then(AnyCallback acceptCallback, AnyCallback rejectCallback);
+    [Custom] Future catch(AnyCallback rejectCallback);
+    [Custom] void done(AnyCallback acceptCallback, AnyCallback rejectCallback);
 };