refactor(render): use render layer fully

Introduces angular2/src/core/compiler/ViewFactory which
extracts ProtoView.instantiate and replaces ViewPool.

Note: This is a work in progress commit to unblock other commits.
There will be follow ups to add unit tests, remove TODOs, …

modules/angular2/test/services/ruler_spec.js

@@ -1,7 +1,7 @@
 import {AsyncTestCompleter, inject, ddescribe, describe, it, iit, xit, expect, SpyObject} from 'angular2/test_lib';
 
 import {DOM, DomAdapter} from 'angular2/src/dom/dom_adapter';
-import {NgElement} from 'angular2/src/core/dom/element';
+import {NgElement} from 'angular2/src/core/compiler/ng_element';
 
 import {Ruler, Rectangle} from 'angular2/src/services/ruler';
 import {createRectangle} from './rectangle_mock';
@@ -35,7 +35,7 @@ export function main() {
       inject([AsyncTestCompleter], (async) => {
         var ruler = new Ruler(new DomAdapterMock(createRectangle(10, 20, 200, 100)));
 
-        ruler.measure(new NgElement(null)).then((rect) => {
+        ruler.measure(new FakeNgElement(null)).then((rect) => {
           assertDimensions(rect, 10, 210, 20, 120, 200, 100);
           async.done();
         });
@@ -46,7 +46,7 @@ export function main() {
       inject([AsyncTestCompleter], (async) => {
         var ruler = new Ruler(DOM);
 
-        ruler.measure(new NgElement(DOM.createElement('div'))).then((rect) => {
+        ruler.measure(new FakeNgElement(DOM.createElement('div'))).then((rect) => {
           //here we are using an element created in a doc fragment so all the measures will come back as 0
           assertDimensions(rect, 0, 0, 0, 0, 0, 0);
           async.done();
@@ -55,3 +55,16 @@ export function main() {
 
   });
 }
+
+class FakeNgElement extends NgElement {
+  _domElement;
+
+  constructor(domElement) {
+    super(null, null);
+    this._domElement = domElement;
+  }
+
+  get domElement() {
+    return this._domElement;
+  }
+}