Replace at-/de-tached with dis-connectedCallback

attached() and detached() are Polymer 1 legacy.

Change-Id: Ic86d07bfb95ec316880db261a913004f5a6e5a22
diff --git a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
index c839118..5a84d9c 100644
--- a/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
+++ b/polygerrit-ui/app/elements/shared/gr-comment/gr-comment.ts
@@ -281,8 +281,8 @@
   reporting = appContext.reportingService;
 
   /** @override */
-  attached() {
-    super.attached();
+  connectedCallback() {
+    super.connectedCallback();
     this.restApiService.getAccount().then(account => {
       this._selfAccount = account;
     });
@@ -297,14 +297,14 @@
   }
 
   /** @override */
-  detached() {
-    super.detached();
+  disconnectedCallback() {
     this.cancelDebouncer(DEBOUNCER_FIRE_UPDATE);
     this.cancelDebouncer(DEBOUNCER_STORE);
     this.cancelDebouncer(DEBOUNCER_DRAFT_TOAST);
     if (this.textarea) {
       this.textarea.closeDropdown();
     }
+    super.disconnectedCallback();
   }
 
   _getAuthor(comment: UIComment) {