feat(core): Add a long-form syntax for Angular bootstrapping.

This change adds a syntax for bootstrapping Angular on a page that allows more fine-grained control of the hierarchy created. platform() creates a platform injector (of which there can only be one). From the platform, .application() creates an Angular application including a Zone and all specified application bindings (e.g. for the DOM, HTTP, Compiler, Renderer, etc). At the application level, .bootstrap() will bootstrap the given component into that application.

Closes #3852

modules/angular2/src/core/testability/browser_testability.dart

@@ -1,4 +1,4 @@
-library testability.get_testability;
+library testability.browser_testability;
 
 import './testability.dart';
 
@@ -80,8 +80,14 @@ class PublicTestability implements _JsObjectProxyable {
   }
 }
 
-class GetTestability {
-  static addToWindow(TestabilityRegistry registry) {
+class BrowserGetTestability implements GetTestability {
+  const BrowserGetTestability();
+
+  static init() {
+    setTestabilityGetter(const BrowserGetTestability());
+  }
+  
+  void addToWindow(TestabilityRegistry registry) {
     var jsRegistry = js.context['ngTestabilityRegistries'];
     if (jsRegistry == null) {
       js.context['ngTestabilityRegistries'] = jsRegistry = new js.JsArray();
@@ -106,10 +112,10 @@ class GetTestability {
         return _jsify(result);
       });
     }
-    jsRegistry.add(_createRegistry(registry));
+    jsRegistry.add(this._createRegistry(registry));
   }
 
-  static js.JsObject _createRegistry(TestabilityRegistry registry) {
+  js.JsObject _createRegistry(TestabilityRegistry registry) {
     var object = new js.JsObject(js.context['Object']);
     object['getAngularTestability'] = _jsify((Element elem,
         bool findInAncestors) {

modules/angular2/src/core/testability/browser_testability.ts

@@ -1,4 +1,9 @@
-import {TestabilityRegistry, Testability} from 'angular2/src/core/testability/testability';
+import {
+  TestabilityRegistry,
+  Testability,
+  GetTestability,
+  setTestabilityGetter
+} from 'angular2/src/core/testability/testability';
 import {global} from 'angular2/src/core/facade/lang';
 
 class PublicTestability {
@@ -13,8 +18,10 @@ class PublicTestability {
   }
 }
 
-export class GetTestability {
-  static addToWindow(registry: TestabilityRegistry) {
+export class BrowserGetTestability implements GetTestability {
+  static init() { setTestabilityGetter(new BrowserGetTestability()); }
+
+  addToWindow(registry: TestabilityRegistry): void {
     global.getAngularTestability = function(elem: Element, findInAncestors: boolean = true):
         PublicTestability {
           var testability = registry.findTestabilityInTree(elem, findInAncestors);

modules/angular2/src/core/testability/testability.ts

@@ -1,8 +1,8 @@
 import {Injectable} from 'angular2/src/core/di';
 import {DOM} from 'angular2/src/core/dom/dom_adapter';
 import {Map, MapWrapper, ListWrapper} from 'angular2/src/core/facade/collection';
+import {CONST, CONST_EXPR} from 'angular2/src/core/facade/lang';
 import {BaseException, WrappedException} from 'angular2/src/core/facade/exceptions';
-import * as getTestabilityModule from './get_testability';
 import {NgZone} from '../zone/ng_zone';
 import {PromiseWrapper} from 'angular2/src/core/facade/async';
 
@@ -76,7 +76,7 @@ export class Testability {
 export class TestabilityRegistry {
   _applications: Map<any, Testability> = new Map();
 
-  constructor() { getTestabilityModule.GetTestability.addToWindow(this); }
+  constructor() { testabilityGetter.addToWindow(this); }
 
   registerApplication(token: any, testability: Testability) {
     this._applications.set(token, testability);
@@ -99,3 +99,16 @@ export class TestabilityRegistry {
     return this.findTestabilityInTree(DOM.parentElement(elem));
   }
 }
+
+export interface GetTestability { addToWindow(registry: TestabilityRegistry): void; }
+
+@CONST()
+class NoopGetTestability implements GetTestability {
+  addToWindow(registry: TestabilityRegistry): void {}
+}
+
+export function setTestabilityGetter(getter: GetTestability): void {
+  testabilityGetter = getter;
+}
+
+var testabilityGetter: GetTestability = CONST_EXPR(new NoopGetTestability());