Remove the compile time flag for DATALIST Element.

Source/core/page/DOMWindow.idl

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Google 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 353 matching lines @@
     attribute HTMLElementConstructor HTMLElement;
     attribute HTMLAnchorElementConstructor HTMLAnchorElement;
     attribute HTMLAppletElementConstructor HTMLAppletElement;
     attribute HTMLAreaElementConstructor HTMLAreaElement;
     attribute HTMLBRElementConstructor HTMLBRElement;
     attribute HTMLBaseElementConstructor HTMLBaseElement;
     attribute HTMLBodyElementConstructor HTMLBodyElement;
     attribute HTMLButtonElementConstructor HTMLButtonElement;
     attribute HTMLCanvasElementConstructor HTMLCanvasElement;
     attribute HTMLDListElementConstructor HTMLDListElement;
-    [Conditional=DATALIST_ELEMENT] attribute HTMLDataListElementConstructor HTMLDataListElement;
+    attribute HTMLDataListElementConstructor HTMLDataListElement;
     [EnabledPerContext=dialogElement] attribute HTMLDialogElementConstructor HTMLDialogElement;
     attribute HTMLDirectoryElementConstructor HTMLDirectoryElement;
     attribute HTMLDivElementConstructor HTMLDivElement;
     attribute HTMLEmbedElementConstructor HTMLEmbedElement;
     attribute HTMLFieldSetElementConstructor HTMLFieldSetElement;
     attribute HTMLFontElementConstructor HTMLFontElement;
     attribute HTMLFormElementConstructor HTMLFormElement;
     attribute HTMLFrameElementConstructor HTMLFrameElement;
     attribute HTMLFrameSetElementConstructor HTMLFrameSetElement;
     attribute HTMLHRElementConstructor HTMLHRElement;
@@ skipping 361 matching lines @@
     attribute MutationRecordConstructor MutationRecord;
 
     [EnabledAtRuntime=mediaSource] attribute MediaSourceConstructor WebKitMediaSource;
     [EnabledAtRuntime=mediaSource] attribute SourceBufferConstructor WebKitSourceBuffer;
     [EnabledAtRuntime=mediaSource] attribute SourceBufferListConstructor WebKitSourceBufferList;
 
     // window.toString() requires special handling in V8
     [DoNotCheckSignature, DoNotCheckSecurity, Custom, NotEnumerable] DOMString toString();
 };