perf: improve baseline speed by 30%

Use node.firstChild and node.nextSibling instead 
of node.children or node.childNodes in the baseline
benchmark.

modules/benchmarks/src/tree/tree_benchmark.js

@@ -191,12 +191,9 @@ function buildTree(maxDepth, values, curDepth) {
       buildTree(maxDepth, values, curDepth+1));
 }
 
-var BASELINE_TEMPLATE = DOM.createTemplate(`
-    <span> {{}}
-       <template class="ng-binding"></template>
-       <template class="ng-binding"></template>
-    </span>`);
-
+var BASELINE_TEMPLATE = DOM.createTemplate(
+    '<span>_<template class="ng-binding"></template><template class="ng-binding"></template></span>');
+// http://jsperf.com/nextsibling-vs-childnodes
 
 class BaseLineTreeComponent {
   element:Element;
@@ -205,13 +202,16 @@ class BaseLineTreeComponent {
   right:BaseLineIf;
   constructor() {
     this.element = DOM.createElement('span');
-    var clone = DOM.clone(BASELINE_TEMPLATE.content.children[0]);
+    var clone = DOM.clone(BASELINE_TEMPLATE.content.firstChild);
     var shadowRoot = this.element.createShadowRoot();
     DOM.appendChild(shadowRoot, clone);
 
-    this.value = new BaseLineInterpolation(clone.childNodes[0]);
-    this.left = new BaseLineIf(clone.children[0]);
-    this.right = new BaseLineIf(clone.children[1]);
+    var child = clone.firstChild;
+    this.value = new BaseLineInterpolation(child);
+    child = DOM.nextSibling(child);
+    this.left = new BaseLineIf(child);
+    child = DOM.nextSibling(child);
+    this.right = new BaseLineIf(child);
   }
   update(value:TreeNode) {
     this.value.update(value.value);

modules/examples/pubspec.yaml

@@ -16,3 +16,6 @@ dev_dependencies:
 transformers:
   - $dart2js:
       minify: true
+      commandLineOptions: [--trust-type-annotations, --trust-primitives, --dump-info]
+      #commandLineOptions: [--trust-type-annotations, --dump-info]
+      #commandLineOptions: [--dump-info]

modules/facade/src/dom.dart

@@ -38,6 +38,9 @@ class DOM {
   static Node firstChild(el) {
     return el.firstChild;
   }
+  static Node nextSibling(el) {
+    return el.nextNode;
+  }
   static Element parentElement(el) {
     return el.parent;
   }

modules/facade/src/dom.es6

@@ -31,6 +31,9 @@ export class DOM {
   static firstChild(el):Node {
     return el.firstChild;
   }
+  static nextSibling(el):Node {
+    return el.nextSibling;
+  }
   static parentElement(el) {
     return el.parentElement;
   }