Oilpan: Make the Node hierarchy RefCountedGarbageCollected instead of TreeShared.

LayoutTests/resources/leak-check.js

 // include resources/js-test.js before this file.
 
-function getCounterValues() {
+function getCounterValues(callback) {
     testRunner.resetTestHelperControllers();
-    gc();
+    asyncGC(function() {
+        var ret = {'numberOfLiveDocuments': window.internals.numberOfLiveDocuments()};
 
-    var ret = {'numberOfLiveDocuments': window.internals.numberOfLiveDocuments()};
+        var refCountedInstances = JSON.parse(window.internals.dumpRefCountedInstanceCounts());
+        for (typename in refCountedInstances)
+            ret['numberOfInstances-'+typename] = refCountedInstances[typename];
 
-    var refCountedInstances = JSON.parse(window.internals.dumpRefCountedInstanceCounts());
-    for (typename in refCountedInstances)
-        ret['numberOfInstances-'+typename] = refCountedInstances[typename];
+        callback(ret);
+    });
 
-    return ret;
 }
 
 function compareValues(countersBefore, countersAfter, tolerance) {
     for (type in tolerance) {
         var before = countersBefore[type];
         var after = countersAfter[type];
 
         if (after - before <= tolerance[type])
             testPassed('The difference of counter "'+type+'" before and after the cycle is under the threshold of '+tolerance[type]+'.');
         else
@@ skipping 18 matching lines @@
     }
 
     jsTestIsAsync = true;
     if (!window.internals) {
         debug("This test only runs on DumpRenderTree, as it requires existence of window.internals and cross-domain resource access check disabled.");
         finishJSTest();
     }
 
     loadSourceIntoIframe('about:blank', function() {
         // blank document loaded...
-        var countersBefore = getCounterValues();
+        getCounterValues(function(countersBefore) {
+            loadSourceIntoIframe(src, function() {
+                // target document loaded...
 
-        loadSourceIntoIframe(src, function() {
-            // target document loaded...
+                loadSourceIntoIframe('about:blank', function() {
+                    // target document unloaded...
 
-            loadSourceIntoIframe('about:blank', function() {
-                // target document unloaded...
-
-                // Measure counter values on next timer event. This is needed
-                // to correctly handle deref cycles for some ActiveDOMObjects
-                // such as XMLHttpRequest.
-                setTimeout(function() {
-                    var countersAfter = getCounterValues();
-                    compareValues(countersBefore, countersAfter, tolerance);
-                    finishJSTest();
-                }, 0);
+                    // Measure counter values on next timer event. This is needed
+                    // to correctly handle deref cycles for some ActiveDOMObjects
+                    // such as XMLHttpRequest.
+                    setTimeout(function() {
+                        getCounterValues(function(countersAfter) {
+                            compareValues(countersBefore, countersAfter, tolerance);
+                            finishJSTest();
+                        });
+                    }, 0);
+                });
             });
         });
     });
 }
 
 function htmlToUrl(html) {
     return 'data:text/html;charset=utf-8,' + html;
 }
 
 function grabScriptText(id) {
     return document.getElementById(id).innerText;
 }
 
 // include fast/js/resources/js-test-post.js after this file.