feat(dialog): allow setting the layout direction (#4778)

Allows users to set the layout direction of a dialog.

src/lib/dialog/dialog-config.ts

@@ -1,4 +1,5 @@
 import {ViewContainerRef} from '@angular/core';
+import {LayoutDirection} from '../core';
 
 /** Valid ARIA roles for a dialog element. */
 export type DialogRole = 'dialog' | 'alertdialog';
@@ -51,5 +52,8 @@ export class MdDialogConfig {
   /** Data being injected into the child component. */
   data?: any = null;
 
+  /** Layout direction for the dialog's content. */
+  direction?: LayoutDirection = 'ltr';
+
   // TODO(jelbourn): add configuration for lifecycle hooks, ARIA labelling.
 }

src/lib/dialog/dialog.spec.ts

@@ -312,6 +312,16 @@ describe('MdDialog', () => {
     expect(overlayPane.style.width).toBe('200px');
   });
 
+  it('should allow setting the layout direction', () => {
+    let dialogRef = dialog.open(PizzaMsg, { direction: 'rtl' });
+
+    viewContainerFixture.detectChanges();
+
+    let overlayPane = overlayContainerElement.querySelector('.cdk-overlay-pane');
+
+    expect(overlayPane.getAttribute('dir')).toBe('rtl');
+  });
+
   it('should close all of the dialogs', async(() => {
     dialog.open(PizzaMsg);
     dialog.open(PizzaMsg);

src/lib/dialog/dialog.ts

@@ -127,6 +127,7 @@ export class MdDialog {
     overlayState.panelClass = dialogConfig.panelClass;
     overlayState.hasBackdrop = dialogConfig.hasBackdrop;
     overlayState.scrollStrategy = this._overlay.scrollStrategies.block();
+    overlayState.direction = dialogConfig.direction;
     if (dialogConfig.backdropClass) {
       overlayState.backdropClass = dialogConfig.backdropClass;
     }