fix(dialog): use injector from viewContainerRef if provided (#2655)

* Right now the `MdDialog` always instantiates the user-provided component with the injector from the `MdDialog` service.

   This is not valid, because developers can provide the `viewContainerRef` to create their dialog in the desired component structure and also expect the parent injector to be the same as in the `viewContainerRef`.

src/lib/dialog/dialog.spec.ts

@@ -8,7 +8,7 @@ import {
   tick,
 } from '@angular/core/testing';
 import {By} from '@angular/platform-browser';
-import {NgModule, Component, Directive, ViewChild, ViewContainerRef} from '@angular/core';
+import {NgModule, Component, Directive, ViewChild, ViewContainerRef, Injector} from '@angular/core';
 import {MdDialogModule} from './index';
 import {MdDialog} from './dialog';
 import {OverlayContainer} from '../core';
@@ -64,6 +64,21 @@ describe('MdDialog', () => {
     expect(dialogContainerElement.getAttribute('role')).toBe('dialog');
   });
 
+  it('should use injector from viewContainerRef for DialogInjector', () => {
+    let dialogRef = dialog.open(PizzaMsg, {
+      viewContainerRef: testViewContainerRef
+    });
+
+    viewContainerFixture.detectChanges();
+
+    let dialogInjector = dialogRef.componentInstance.dialogInjector;
+
+    expect(dialogRef.componentInstance.dialogRef).toBe(dialogRef);
+    expect(dialogInjector.get(DirectiveWithViewContainer)).toBeTruthy(
+      'Expected the dialog component to be created with the injector from the viewContainerRef.'
+    );
+  });
+
   it('should open a dialog with a component and no ViewContainerRef', () => {
     let dialogRef = dialog.open(PizzaMsg);
 
@@ -435,7 +450,8 @@ class ComponentWithChildViewContainer {
 /** Simple component for testing ComponentPortal. */
 @Component({template: '<p>Pizza</p> <input> <button>Close</button>'})
 class PizzaMsg {
-  constructor(public dialogRef: MdDialogRef<PizzaMsg>) { }
+  constructor(public dialogRef: MdDialogRef<PizzaMsg>,
+              public dialogInjector: Injector) {}
 }
 
 @Component({

src/lib/dialog/dialog.ts

@@ -42,7 +42,7 @@ export class MdDialog {
 
     let overlayRef = this._createOverlay(config);
     let dialogContainer = this._attachDialogContainer(overlayRef, config);
-    let dialogRef = this._attachDialogContent(component, dialogContainer, overlayRef);
+    let dialogRef = this._attachDialogContent(component, dialogContainer, overlayRef, config);
 
     this._openDialogs.push(dialogRef);
     dialogRef.afterClosed().subscribe(() => this._removeOpenDialog(dialogRef));
@@ -96,12 +96,14 @@ export class MdDialog {
    * @param component The type of component being loaded into the dialog.
    * @param dialogContainer Reference to the wrapping MdDialogContainer.
    * @param overlayRef Reference to the overlay in which the dialog resides.
+   * @param config The dialog configuration.
    * @returns A promise resolving to the MdDialogRef that should be returned to the user.
    */
   private _attachDialogContent<T>(
       component: ComponentType<T>,
       dialogContainer: MdDialogContainer,
-      overlayRef: OverlayRef): MdDialogRef<T> {
+      overlayRef: OverlayRef,
+      config?: MdDialogConfig): MdDialogRef<T> {
     // Create a reference to the dialog we're creating in order to give the user a handle
     // to modify and close it.
     let dialogRef = <MdDialogRef<T>> new MdDialogRef(overlayRef);
@@ -117,7 +119,8 @@ export class MdDialog {
     // We create an injector specifically for the component we're instantiating so that it can
     // inject the MdDialogRef. This allows a component loaded inside of a dialog to close itself
     // and, optionally, to return a value.
-    let dialogInjector = new DialogInjector(dialogRef, this._injector);
+    let userInjector = config && config.viewContainerRef && config.viewContainerRef.injector;
+    let dialogInjector = new DialogInjector(dialogRef, userInjector || this._injector);
 
     let contentPortal = new ComponentPortal(component, null, dialogInjector);