Issue #1322 - Part 3: Remove DOM promise interface gunk

Based on work by Boris Zbarsky

dom/webidl/Promise.webidl

@@ -3,28 +3,15 @@
  * 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
- * http://dom.spec.whatwg.org/#promises
+ * This IDL file contains utilities to help connect JS promises to our
+ * Web IDL infrastructure.
  */
 
-// TODO We use object instead Function.  There is an open issue on WebIDL to
-// have different types for "platform-provided function" and "user-provided
-// function"; for now, we just use "object".
-callback PromiseInit = void (object resolve, object reject);
-
 callback PromiseJobCallback = void();
 
 [TreatNonCallableAsNull]
 callback AnyCallback = any (any value);
 
-// Promises are implemented in SpiderMonkey; just define a tiny interface to make
-// codegen of Promise arguments and return values work.
-[NoInterfaceObject,
- Exposed=(Window,Worker,WorkerDebugger,System)]
-// Need to escape "Promise" so it's treated as an identifier.
-interface _Promise {
-};
-
 // Hack to allow us to have JS owning and properly tracing/CCing/etc a
 // PromiseNativeHandler.
 [NoInterfaceObject,