Introduce WindowTimers IDL interface

Source/core/workers/WorkerContext.idl

Index: Source/core/workers/WorkerContext.idl
diff --git a/Source/core/workers/WorkerContext.idl b/Source/core/workers/WorkerContext.idl
index e513baf1c1aeaf657fb7ed3f4498a8ba5bf53645..9c4ff2b27ffba21368093bfe629b76dd082dd3ea 100644
--- a/Source/core/workers/WorkerContext.idl
+++ b/Source/core/workers/WorkerContext.idl
@@ -41,13 +41,6 @@
     [Custom] void importScripts(/*[Variadic] in DOMString urls */);
              [Replaceable] readonly attribute WorkerNavigator navigator;
 
-    // Timers
-    [Custom] long setTimeout(any handler, [Default=Undefined] optional long timeout);
-    void clearTimeout([Default=Undefined] optional long handle);
-    [Custom] long setInterval(any handler, [Default=Undefined] optional long timeout);
-    void clearInterval([Default=Undefined] optional long handle);
-
-
     // EventTarget interface
     void addEventListener(DOMString type, 
                           EventListener listener, 
@@ -61,3 +54,5 @@
     attribute URLConstructor webkitURL; // FIXME: deprecate this.
 };
 
+WorkerContext implements WindowTimers;
+