fix(autocomplete): aria-expanded should be updated when panel hides

Author: kara

src/lib/autocomplete/autocomplete-trigger.ts

@@ -114,7 +114,7 @@ export class MdAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
 
   /* Whether or not the autocomplete panel is open. */
   get panelOpen(): boolean {
-    return this._panelOpen;
+    return this._panelOpen && this.autocomplete.showPanel;
   }
 
   /** Opens the autocomplete suggestion panel. */

src/lib/autocomplete/autocomplete.spec.ts

@@ -762,6 +762,27 @@ describe('MdAutocomplete', () => {
       });
     }));
 
+    it('should set aria-expanded properly when the panel is hidden', async(() => {
+        fixture.componentInstance.trigger.openPanel();
+
+        fixture.whenStable().then(() => {
+          fixture.detectChanges();
+          expect(input.getAttribute('aria-expanded'))
+              .toBe('true', 'Expected aria-expanded to be true while panel is open.');
+
+          typeInElement('zz', input);
+          fixture.whenStable().then(() => {
+            fixture.detectChanges();
+
+            fixture.whenStable().then(() => {
+              fixture.detectChanges();
+              expect(input.getAttribute('aria-expanded'))
+                .toBe('false', 'Expected aria-expanded to be false when panel hides itself.');
+            });
+          });
+        });
+    }));
+
     it('should set aria-owns based on the attached autocomplete', () => {
       fixture.componentInstance.trigger.openPanel();
       fixture.detectChanges();