Use enum BinaryType for WebSocket.binaryType, instead of DOMString

Source/modules/websockets/WebSocket.idl

 /*
  * Copyright (C) 2009 Google Inc.  All rights reserved.
  * Copyright (C) 2010, 2011 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 13 matching lines @@
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 // https://html.spec.whatwg.org/multipage/comms.html#the-websocket-interface
 
-// FIXME: use BinaryType in binaryType
 enum BinaryType { "blob", "arraybuffer" };
 
 [
     ActiveDOMObject,
     // FIXME: Spec has DOMString[]. https://www.w3.org/Bugs/Public/show_bug.cgi?id=28102
     Constructor(DOMString url, optional (DOMString or sequence<DOMString>) protocols),
     ConstructorCallWith=ExecutionContext,
     Exposed=(Window,Worker),
     TypeChecking=Interface,
     RaisesException=Constructor,
@@ skipping 15 matching lines @@
     attribute EventHandler onerror;
     attribute EventHandler onclose;
     // FIXME: Per spec and impl, should never return undefined. Verify and remove extended attribute.
     [TreatReturnedNullStringAs=Undefined] readonly attribute DOMString extensions;
     // FIXME: Per spec and impl, should never return undefined. Verify and remove extended attribute.
     [TreatReturnedNullStringAs=Undefined] readonly attribute DOMString protocol;
     [RaisesException] void close([Clamp] optional unsigned short code, optional USVString reason);
 
     // messaging
     attribute EventHandler onmessage;
-    attribute DOMString binaryType;
+    attribute BinaryType binaryType;
     [RaisesException] void send(USVString data);
     [RaisesException] void send(Blob data);
     [RaisesException] void send(ArrayBuffer data);
     [RaisesException] void send(ArrayBufferView data);
 };