feat(sidenav): add disableClose option (#2501)

* feat(sidenav): add disableClose option

* Adds an attribute to the `md-sidenav` component, which allows developers to disable the closing behavior (e.g escape closing)
  Backdrop stays separate because you can disable it by using the `mode` attribute.

Closes #2462

* Address comments

src/lib/sidenav/sidenav.spec.ts

@@ -194,7 +194,7 @@ describe('MdSidenav', () => {
       }).not.toThrow();
     }));
 
-    it('should emit the backdrop-clicked event when the backdrop is clicked', fakeAsync(() => {
+    it('should emit the backdropClick event when the backdrop is clicked', fakeAsync(() => {
       let fixture = TestBed.createComponent(BasicTestApp);
 
       let testComponent: BasicTestApp = fixture.debugElement.componentInstance;
@@ -264,6 +264,54 @@ describe('MdSidenav', () => {
       expect(testComponent.closeCount).toBe(1);
     }));
 
+    it('should not close by pressing escape when disableClose is set', fakeAsync(() => {
+      let fixture = TestBed.createComponent(BasicTestApp);
+      let testComponent = fixture.debugElement.componentInstance;
+      let sidenav = fixture.debugElement.query(By.directive(MdSidenav)).componentInstance;
+
+      sidenav.disableClose = true;
+      sidenav.open();
+
+      fixture.detectChanges();
+      endSidenavTransition(fixture);
+      tick();
+
+      sidenav.handleKeydown({
+        keyCode: ESCAPE,
+        stopPropagation: () => {}
+      });
+
+      fixture.detectChanges();
+      endSidenavTransition(fixture);
+      tick();
+
+      expect(testComponent.closeCount).toBe(0);
+    }));
+
+    it('should not close by clicking on the backdrop when disableClose is set', fakeAsync(() => {
+      let fixture = TestBed.createComponent(BasicTestApp);
+      let testComponent = fixture.debugElement.componentInstance;
+      let sidenav = fixture.debugElement.query(By.directive(MdSidenav)).componentInstance;
+
+      sidenav.disableClose = true;
+      sidenav.open();
+
+      fixture.detectChanges();
+      endSidenavTransition(fixture);
+      tick();
+
+      let backdropEl = fixture.debugElement.query(By.css('.md-sidenav-backdrop')).nativeElement;
+      backdropEl.click();
+      fixture.detectChanges();
+      tick();
+
+      fixture.detectChanges();
+      endSidenavTransition(fixture);
+      tick();
+
+      expect(testComponent.closeCount).toBe(0);
+    }));
+
     it('should restore focus to the trigger element on close', fakeAsync(() => {
       let fixture = TestBed.createComponent(BasicTestApp);
       let sidenav: MdSidenav = fixture.debugElement
@@ -414,7 +462,7 @@ class SidenavContainerTwoSidenavTestApp { }
 /** Test component that contains an MdSidenavContainer and one MdSidenav. */
 @Component({
   template: `
-    <md-sidenav-container (backdrop-clicked)="backdropClicked()">
+    <md-sidenav-container (backdropClick)="backdropClicked()">
       <md-sidenav #sidenav align="start"
                   (open-start)="openStart()"
                   (open)="open()"

src/lib/sidenav/sidenav.ts

@@ -102,6 +102,12 @@ export class MdSidenav implements AfterContentInit {
   /** Mode of the sidenav; whether 'over' or 'side'. */
   @Input() mode: 'over' | 'push' | 'side' = 'over';
 
+  /** Whether the sidenav can be closed with the escape key or not. */
+  @Input()
+  get disableClose(): boolean { return this._disableClose; }
+  set disableClose(value: boolean) { this._disableClose = coerceBooleanProperty(value); }
+  private _disableClose: boolean = false;
+
   /** Whether the sidenav is opened. */
   _opened: boolean = false;
 
@@ -232,7 +238,7 @@ export class MdSidenav implements AfterContentInit {
    * @docs-private
    */
   handleKeydown(event: KeyboardEvent) {
-    if (event.keyCode === ESCAPE) {
+    if (event.keyCode === ESCAPE && !this.disableClose) {
       this.close();
       event.stopPropagation();
     }
@@ -327,7 +333,7 @@ export class MdSidenavContainer implements AfterContentInit {
   get end() { return this._end; }
 
   /** Event emitted when the sidenav backdrop is clicked. */
-  @Output('backdrop-clicked') onBackdropClicked = new EventEmitter<void>();
+  @Output() backdropClick = new EventEmitter<void>();
 
   /** The sidenav at the start/end alignment, independent of direction. */
   private _start: MdSidenav;
@@ -434,17 +440,15 @@ export class MdSidenavContainer implements AfterContentInit {
   }
 
   _onBackdropClicked() {
-    this.onBackdropClicked.emit();
+    this.backdropClick.emit();
     this._closeModalSidenav();
   }
 
   _closeModalSidenav() {
-    if (this._start != null && this._start.mode != 'side') {
-      this._start.close();
-    }
-    if (this._end != null && this._end.mode != 'side') {
-      this._end.close();
-    }
+    // Close all open sidenav's where closing is not disabled and the mode is not `side`.
+    [this._start, this._end]
+      .filter(sidenav => sidenav && !sidenav.disableClose && sidenav.mode !== 'side')
+      .forEach(sidenav => sidenav.close());
   }
 
   _isShowingBackdrop(): boolean {