fix(material/dialog): macOS dialog title not read in chrome and firefox

Fixes issue with Angular Components Dialog component where VoiceOver
does not read the dialog name if the dialog is supposed to be read by
aria-labelledby or aria-describedby attributes. Updates dialog-container.ts
so that the aria-labelledby or aria-described by value (if any) is used
as an aria-label value.

Fixes b/274674581

src/cdk/dialog/dialog-container.ts

@@ -68,7 +68,7 @@ export function throwDialogContentAlreadyAttachedError() {
     '[attr.aria-modal]': '_config.ariaModal',
     '[attr.aria-labelledby]': '_config.ariaLabel ? null : _ariaLabelledByQueue[0]',
     '[attr.aria-label]': '_config.ariaLabel',
-    '[attr.aria-describedby]': '_config.ariaDescribedBy || null',
+    '[attr.aria-describedby]': '_config.ariaLabel ? null : _ariaDescribedByQueue[0]',
   },
 })
 export class CdkDialogContainer<C extends DialogConfig = DialogConfig>
@@ -94,6 +94,8 @@ export class CdkDialogContainer<C extends DialogConfig = DialogConfig>
    */
   _closeInteractionType: FocusOrigin | null = null;
 
+  _ariaLabel: string;
+
   /**
    * Queue of the IDs of the dialog's label element, based on their definition order. The first
    * ID will be used as the `aria-labelledby` value. We use a queue here to handle the case
@@ -102,6 +104,14 @@ export class CdkDialogContainer<C extends DialogConfig = DialogConfig>
    */
   _ariaLabelledByQueue: string[] = [];
 
+  /**
+   * Queue of the IDs of the dialog's label element, based on their definition order. The first
+   * ID will be used as the `aria-describedby` value. We use a queue here to handle the case
+   * where there are two or more titles in the DOM at a time and the first one is destroyed while
+   * the rest are present.
+   */
+  _ariaDescribedByQueue: string[] = [];
+
   protected readonly _changeDetectorRef = inject(ChangeDetectorRef);
 
   private _injector = inject(Injector);
@@ -122,9 +132,17 @@ export class CdkDialogContainer<C extends DialogConfig = DialogConfig>
 
     this._document = _document;
 
+    console.log('inside constructor this._config');
+    console.log(this._config);
+    if (this._config.ariaLabel) {
+      this._ariaLabel = this._config.ariaLabel;
+    }
     if (this._config.ariaLabelledBy) {
       this._ariaLabelledByQueue.push(this._config.ariaLabelledBy);
     }
+    if (this._config.ariaDescribedBy) {
+      this._ariaDescribedByQueue.push(this._config.ariaDescribedBy);
+    }
   }
 
   _addAriaLabelledBy(id: string) {
@@ -141,6 +159,20 @@ export class CdkDialogContainer<C extends DialogConfig = DialogConfig>
     }
   }
 
+  _addAriaDescribedBy(id: string) {
+    this._ariaDescribedByQueue.push(id);
+    this._changeDetectorRef.markForCheck();
+  }
+
+  _removeAriaDescribedBy(id: string) {
+    const index = this._ariaDescribedByQueue.indexOf(id);
+
+    if (index > -1) {
+      this._ariaDescribedByQueue.splice(index, 1);
+      this._changeDetectorRef.markForCheck();
+    }
+  }
+
   protected _contentAttached() {
     this._initializeFocusTrap();
     this._handleBackdropClicks();

src/material/dialog/dialog-container.ts

@@ -10,6 +10,7 @@ import {FocusMonitor, FocusTrapFactory, InteractivityChecker} from '@angular/cdk
 import {OverlayRef} from '@angular/cdk/overlay';
 import {DOCUMENT} from '@angular/common';
 import {
+  AfterViewInit,
   ChangeDetectionStrategy,
   Component,
   ComponentRef,
@@ -25,7 +26,9 @@ import {
 import {MatDialogConfig} from './dialog-config';
 import {CdkDialogContainer} from '@angular/cdk/dialog';
 import {coerceNumberProperty} from '@angular/cdk/coercion';
+import {PlatformModule} from '@angular/cdk/platform';
 import {CdkPortalOutlet, ComponentPortal} from '@angular/cdk/portal';
+import {Observable, Subject, Subscription, defer, fromEvent, merge, of as observableOf} from 'rxjs';
 
 /** Event that captures the state of dialog container animations. */
 interface LegacyDialogAnimationEvent {
@@ -71,7 +74,10 @@ export const CLOSE_ANIMATION_DURATION = 75;
     '[class.mat-mdc-dialog-container-with-actions]': '_actionSectionCount > 0',
   },
 })
-export class MatDialogContainer extends CdkDialogContainer<MatDialogConfig> implements OnDestroy {
+export class MatDialogContainer
+  extends CdkDialogContainer<MatDialogConfig>
+  implements AfterViewInit, OnDestroy
+{
   /** Emits when an animation state changes. */
   _animationStateChanged = new EventEmitter<LegacyDialogAnimationEvent>();
 
@@ -93,6 +99,11 @@ export class MatDialogContainer extends CdkDialogContainer<MatDialogConfig> impl
     : 0;
   /** Current timer for dialog animations. */
   private _animationTimer: ReturnType<typeof setTimeout> | null = null;
+  /** Platform Observer */
+  // private _userAgentSubscription = Subscription.EMPTY;
+  private _getWindow(): Window {
+    return this._document?.defaultView || window;
+  }
 
   constructor(
     elementRef: ElementRef,
@@ -117,6 +128,30 @@ export class MatDialogContainer extends CdkDialogContainer<MatDialogConfig> impl
     );
   }
 
+  /** Get Dialog name from aria attributes */
+  private _getDialogName = async (): Promise<void> => {
+    const configData = this._config;
+    /**_ariaLabelledByQueue and _ariaDescribedByQueue are created if ariaLabelledBy
+        or ariaDescribedBy values are applied to the dialog config
+    */
+    const ariaLabelledByRefId = await this._ariaLabelledByQueue[0];
+    const ariaDescribedByRefId = await this._ariaDescribedByQueue[0];
+    /** Get Element to get name/title from if ariaLabelledBy or ariaDescribedBy */
+    const dialogNameElement =
+      document.getElementById(ariaLabelledByRefId) || document.getElementById(ariaDescribedByRefId);
+    const dialogNameInnerText =
+      /** If no ariaLabelledBy, ariaDescribedBy, or ariaLabel, create default aria label */
+      !dialogNameElement || !this._config.ariaLabel
+        ? 'Dialog Modal'
+        : /** Otherwise prioritize use of ariaLabel */
+          this._config.ariaLabel || dialogNameElement?.innerText || dialogNameElement?.ariaLabel;
+    return;
+  };
+  ngAfterViewInit() {
+    const window = this._getWindow();
+    this._getDialogName();
+  }
+
   protected override _contentAttached(): void {
     // Delegate to the original dialog-container initialization (i.e. saving the
     // previous element, setting up the focus trap and moving focus to the container).