Refactor show-alert, page-error events

Change-Id: I38b55a8ceaa5819742e819cea0349fcecfb4b1ce
diff --git a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
index ac65297..fde7234 100644
--- a/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
+++ b/polygerrit-ui/app/elements/admin/gr-repo-access/gr-repo-access.ts
@@ -52,7 +52,7 @@
   PropertyTreeNode,
   PrimitiveValue,
 } from './gr-repo-access-interfaces';
-import {EventType, fire} from '../../../utils/event-util';
+import {firePageError, fireAlert} from '../../../utils/event-util';
 
 const NOTHING_TO_SAVE = 'No changes to save.';
 
@@ -155,15 +155,7 @@
   }
 
   _reload(repo: RepoName) {
-    const errFn = (response?: Response | null) => {
-      this.dispatchEvent(
-        new CustomEvent('page-error', {
-          detail: {response},
-          composed: true,
-          bubbles: true,
-        })
-      );
-    };
+    const errFn = (response?: Response | null) => firePageError(this, response);
 
     this._editing = false;
 
@@ -517,7 +509,7 @@
       !Object.keys(addRemoveObj.remove).length &&
       !addRemoveObj.parent
     ) {
-      fire(this, EventType.SHOW_ALERT, NOTHING_TO_SAVE);
+      fireAlert(this, NOTHING_TO_SAVE);
       return;
     }
     const obj: ProjectAccessInput = ({