Cleanup LayoutTests that define a function gc().

third_party/WebKit/LayoutTests/fast/dom/gc-custom-prototype.html

 <p>Tests that custom prototypes on DOM objects persist after garbage collection.</p>
 <pre id="console"></pre>
 
 <p id="p"></p>
-
+<script src="../../resources/gc.js"></script>
 <script>
 function $(id)
 {
     return document.getElementById(id);
 }
 
 function log(s)
 {
     $("console").appendChild(document.createTextNode(s + "\n"));
 }
 
 function shouldBe(aDescription, a, b)
 {
     if (a != b) {
         log("FAIL: " + aDescription + " should be " + b + " but instead is " + a + ".");
         return;
     }
 
     log("PASS: " + aDescription + " should be " + b + " and is.");
 }
 
-function gc()
-{
-    if (window.GCController) {
-        GCController.collect();
-        return;
-    }
-    
-    for (var i = 0; i < 10000; ++i)
-        new Object;
-}
-
 function shouldBeNull(aDescription, a)
 {
     if (a == null) {
         log("PASS: " + aDescription + " should be null and is.");
         return;
     }
     
     log("FAIL: " + aDescription + " should be null but instead is " + a + ".");
 }
 
@@ skipping 13 matching lines @@
 
     shouldBeNonNull("$('p').__proto__", $('p').__proto__);
     $('p').__proto__ = null;
     shouldBeNull("$('p').__proto__", $('p').__proto__);
 
     gc();
 
     shouldBeNull("$('p').__proto__", $('p').__proto__);
 })();
 </script>