refactor(cdk/dialog): Consolidate afterNextRender calls (#29237)

(cherry picked from commit 70780a6)

Author: mmalerba

src/cdk/dialog/dialog-container.ts

@@ -257,61 +257,43 @@ export class CdkDialogContainer<C extends DialogConfig = DialogConfig>
       return;
     }
 
-    const element = this._elementRef.nativeElement;
     // If were to attempt to focus immediately, then the content of the dialog would not yet be
     // ready in instances where change detection has to run first. To deal with this, we simply
-    // wait for the microtask queue to be empty when setting focus when autoFocus isn't set to
-    // dialog. If the element inside the dialog can't be focused, then the container is focused
-    // so the user can't tab into other elements behind it.
-    const autoFocus = this._config.autoFocus;
-    switch (autoFocus) {
-      case false:
-      case 'dialog':
-        // Ensure that focus is on the dialog container. It's possible that a different
-        // component tried to move focus while the open animation was running. See:
-        // https://github.com/angular/components/issues/16215. Note that we only want to do this
-        // if the focus isn't inside the dialog already, because it's possible that the consumer
-        // turned off `autoFocus` in order to move focus themselves.
-        afterNextRender(
-          () => {
+    // wait until after the next render.
+    afterNextRender(
+      () => {
+        const element = this._elementRef.nativeElement;
+        switch (this._config.autoFocus) {
+          case false:
+          case 'dialog':
+            // Ensure that focus is on the dialog container. It's possible that a different
+            // component tried to move focus while the open animation was running. See:
+            // https://github.com/angular/components/issues/16215. Note that we only want to do this
+            // if the focus isn't inside the dialog already, because it's possible that the consumer
+            // turned off `autoFocus` in order to move focus themselves.
             if (!this._containsFocus()) {
               element.focus();
             }
-          },
-          {injector: this._injector},
-        );
-        break;
-      case true:
-      case 'first-tabbable':
-        afterNextRender(
-          () => {
+            break;
+          case true:
+          case 'first-tabbable':
             const focusedSuccessfully = this._focusTrap?.focusInitialElement();
             // If we weren't able to find a focusable element in the dialog, then focus the dialog
             // container instead.
             if (!focusedSuccessfully) {
               this._focusDialogContainer();
             }
-          },
-          {injector: this._injector},
-        );
-        break;
-      case 'first-heading':
-        afterNextRender(
-          () => {
+            break;
+          case 'first-heading':
             this._focusByCssSelector('h1, h2, h3, h4, h5, h6, [role="heading"]');
-          },
-          {injector: this._injector},
-        );
-        break;
-      default:
-        afterNextRender(
-          () => {
-            this._focusByCssSelector(autoFocus!);
-          },
-          {injector: this._injector},
-        );
-        break;
-    }
+            break;
+          default:
+            this._focusByCssSelector(this._config.autoFocus!);
+            break;
+        }
+      },
+      {injector: this._injector},
+    );
   }
 
   /** Restores focus to the element that was focused before the dialog opened. */