Change return type to w3c standard of void for AudioBufferCallback.

lib/html/idl/dart/dart.idl

 
 // This file introduces / supplements and forces Dart declarations.
 
 module default {
   ClientRectList implements sequence<ClientRect>;
   CSSRuleList implements sequence<CSSRule>;
   CSSValueList implements sequence<CSSValue>;
   DOMMimeTypeArray implements sequence<DOMMimeType>;
   DOMPluginArray implements sequence<DOMPlugin>;
   EntryArray implements sequence<Entry>;
@@ skipping 366 matching lines @@
     // overrides.
     [Suppressed] boolean send(in DOMString data) raises(DOMException);
     [Custom] void send(DOMString data) raises(DOMException);
     [Custom] void send(Blob data) raises(DOMException);
     [Custom] void send(ArrayBuffer data) raises(DOMException);
     [Custom] void send(ArrayBufferView data) raises(DOMException);
   };
 }
 
 module core {
-  [Supplemental, Callback]
-  interface RequestAnimationFrameCallback {
-    // Webkit implements this as returning bool, but standard is void.
-    [Suppressed] boolean handleEvent(in DOMTimeStamp time);
-    [Custom] void handleEvent(in DOMTimeStamp time);
-  };
-
   [Suppressed]
   interface Entity {};
 }