feat(NgTemplateOutlet): add NgTemplateOutlet directive

This commits adds a new NgTemplateOutlet directive that can be
used to create embeded views from a supplied TemplateRef.

Closes #7615

Closes #8021

modules/angular2/src/common/directives.ts

@@ -6,6 +6,7 @@
 export {NgClass} from './directives/ng_class';
 export {NgFor} from './directives/ng_for';
 export {NgIf} from './directives/ng_if';
+export {NgTemplateOutlet} from './directives/ng_template_outlet';
 export {NgStyle} from './directives/ng_style';
 export {NgSwitch, NgSwitchWhen, NgSwitchDefault} from './directives/ng_switch';
 export {NgPlural, NgPluralCase, NgLocalization} from './directives/ng_plural';

modules/angular2/src/common/directives/core_directives.ts

@@ -2,6 +2,7 @@ import {CONST_EXPR, Type} from 'angular2/src/facade/lang';
 import {NgClass} from './ng_class';
 import {NgFor} from './ng_for';
 import {NgIf} from './ng_if';
+import {NgTemplateOutlet} from './ng_template_outlet';
 import {NgStyle} from './ng_style';
 import {NgSwitch, NgSwitchWhen, NgSwitchDefault} from './ng_switch';
 import {NgPlural, NgPluralCase} from './ng_plural';
@@ -50,6 +51,7 @@ export const CORE_DIRECTIVES: Type[] = CONST_EXPR([
   NgClass,
   NgFor,
   NgIf,
+  NgTemplateOutlet,
   NgStyle,
   NgSwitch,
   NgSwitchWhen,

modules/angular2/src/common/directives/ng_template_outlet.ts

@@ -0,0 +1,26 @@
+import {Directive, Input, ViewContainerRef, ViewRef, TemplateRef} from 'angular2/core';
+import {isPresent} from 'angular2/src/facade/lang';
+
+/**
+ * Creates and inserts an embedded view based on a prepared `TemplateRef`.
+ *
+ * ### Syntax
+ * - `<template [ngTemplateOutlet]="templateRefExpression"></template>`
+ */
+@Directive({selector: '[ngTemplateOutlet]'})
+export class NgTemplateOutlet {
+  private _insertedViewRef: ViewRef;
+
+  constructor(private _viewContainerRef: ViewContainerRef) {}
+
+  @Input()
+  set ngTemplateOutlet(templateRef: TemplateRef) {
+    if (isPresent(this._insertedViewRef)) {
+      this._viewContainerRef.remove(this._viewContainerRef.indexOf(this._insertedViewRef));
+    }
+
+    if (isPresent(templateRef)) {
+      this._insertedViewRef = this._viewContainerRef.createEmbeddedView(templateRef);
+    }
+  }
+}