perf: force GC on profiles

modules/benchmarks/src/tree/tree_benchmark.js

@@ -8,7 +8,7 @@ import {TemplateLoader} from 'core/compiler/template_loader';
 import {LifeCycle} from 'core/life_cycle/life_cycle';
 
 import {reflector} from 'reflection/reflection';
-import {DOM, document, window, Element} from 'facade/dom';
+import {DOM, document, window, Element, gc} from 'facade/dom';
 import {isPresent} from 'facade/lang';
 
 var MAX_DEPTH = 9;
@@ -137,18 +137,29 @@ export function main() {
 
   function profile(create, destroy, name) {
     return function(_) {
-      window.console.profile(name);
+      window.console.profile(name + ' w GC');
       var duration = 0;
-      var downCount = 200;
       var count = 0;
-      while(downCount--) {
+      while(count++ < 150) {
+        gc();
         var start = window.performance.now();
         create(_);
         duration += window.performance.now() - start;
         destroy(_);
-        count++;
       }
-      window.console.profileEnd(name);
+      window.console.profileEnd(name + ' w GC');
+      window.console.log(`Iterations: ${count}; time: ${duration / count} ms / iteration`);
+
+      window.console.profile(name + ' w/o GC');
+      duration = 0;
+      count = 0;
+      while(count++ < 150) {
+        var start = window.performance.now();
+        create(_);
+        duration += window.performance.now() - start;
+        destroy(_);
+      }
+      window.console.profileEnd(name + ' w/o GC');
       window.console.log(`Iterations: ${count}; time: ${duration / count} ms / iteration`);
     };
   }
@@ -227,6 +238,7 @@ var BASELINE_IF_TEMPLATE = DOM.createTemplate(
 // http://jsperf.com/nextsibling-vs-childnodes
 
 class BaseLineTreeComponent {
+  element:Element;
   value:BaseLineInterpolation;
   left:BaseLineIf;
   right:BaseLineIf;

modules/facade/src/dom.dart

@@ -1,7 +1,7 @@
 library angular.core.facade.dom;
 
 import 'dart:html';
-import 'dart:js' show JsObject;
+import 'dart:js' show JsObject, context;
 
 export 'dart:html' show DocumentFragment, Node, Element, TemplateElement, Text, document, location, window;
 
@@ -11,6 +11,15 @@ class IdentitySanitizer implements NodeTreeSanitizer {
   void sanitizeTree(Node node) {}
 }
 
+var _window = context['window'];
+var _gc = context['gc'];
+
+gc() {
+  if (_gc != null) {
+    _gc.apply(const []);
+  }
+}
+
 final identitySanitizer = new IdentitySanitizer();
 
 class DOM {

modules/facade/src/dom.es6

@@ -7,6 +7,7 @@ export var Element = window.HTMLElement;
 export var TemplateElement = window.HTMLTemplateElement;
 export var document = window.document;
 export var location = window.location;
+export var gc = window.gc ? () => window.gc() : () => null;
 
 import {List, MapWrapper, ListWrapper} from 'facade/collection';