fix(material-experimental/mdc-list): ensure selection change event fires properly

src/material-experimental/mdc-list/selection-list.spec.ts

@@ -424,14 +424,7 @@ describe('MDC-based MatSelectionList without forms', () => {
       expect(listOptions.every(option => option.componentInstance.selected)).toBe(false);
     });
 
-    // This is temporarily disabled as the MDC list does not emit a proper event when
-    // items are interactively toggled with e.g. `CTRL + A`.
-    // TODO(devversion): look more into this. MDC does not expose an `onChange` adapter
-    // function. Authors are required to emit a change event on checkbox/radio change, but
-    // that is not an viable option for us since we also allow for programmatic selection updates.
-    // https://github.com/material-components/material-components-web/blob/a986df922b6b4c1ef5c59925107281d1d40287a8/packages/mdc-list/component.ts#L300-L308.
-    // tslint:disable-next-line:ban
-    xit('should dispatch the selectionChange event when selecting via ctrl + a', () => {
+    it('should dispatch the selectionChange event when selecting via ctrl + a', () => {
       const spy = spyOn(fixture.componentInstance, 'onSelectionChange');
       listOptions.forEach(option => (option.componentInstance.disabled = false));
       fixture.detectChanges();

src/material-experimental/mdc-list/selection-list.ts

@@ -398,8 +398,8 @@ function getSelectionListAdapter(list: MatSelectionList): MDCListAdapter {
 
       baseAdapter.setAttributeForElementIndex(index, attribute, value);
     },
-    notifyAction(index: number): void {
-      list._emitChangeEvent([list._itemsArr[index]]);
+    notifySelectionChange(changedIndices: number[]): void {
+      list._emitChangeEvent(changedIndices.map(index => list._itemsArr[index]));
     },
   };
 }