Fixes for dynamic modal a11y (#518)

* Do not close modal if click finishes on background

* Trap tab focus in modals, use ESC to close modal

* Fix Angular change detection errors in modals

* Reset focus on next modal after closing modal

* Minor fixes and linting

* Attach focusTrap to modal-dialog element

* Change mousedown event back to click

* Make topModal private

* Add new div for dismissing modal by clicking bg

* Focus element in modal if no autoFocus directive

* Use backdrop for dismissal

* Fix typo

angular/src/directives/autofocus.directive.ts

@@ -2,8 +2,11 @@ import {
     Directive,
     ElementRef,
     Input,
+    NgZone,
 } from '@angular/core';
 
+import { take } from 'rxjs/operators';
+
 import { Utils } from 'jslib-common/misc/utils';
 
 @Directive({
@@ -16,11 +19,15 @@ export class AutofocusDirective {
 
     private autofocus: boolean;
 
-    constructor(private el: ElementRef) { }
+    constructor(private el: ElementRef, private ngZone: NgZone) { }
 
     ngOnInit() {
         if (!Utils.isMobileBrowser && this.autofocus) {
-            this.el.nativeElement.focus();
+            if (this.ngZone.isStable) {
+                this.el.nativeElement.focus();
+            } else {
+                this.ngZone.onStable.pipe(take(1)).subscribe(() => this.el.nativeElement.focus());
+            }
         }
     }
 }