fix(material/chips): correct focus management on chip destruction (#33329)

* fix(material/chips): correct focus management on chip destruction

Un-privatized _redirectDestroyedChipFocus to allow MatChipGrid to override the aggressive focus-stealing behavior with a silent updateActiveItem call, respecting downstream layout stability.

Fixes #14345

* Update chip-grid.ts

* Update chip-grid.spec.ts

* Update chip.ts

(cherry picked from commit e49f127)

Author: zsheikh-eng

src/material/chips/chip-grid.spec.ts

@@ -180,6 +180,25 @@ describe('MatChipGrid', () => {
         expect(chipGridNativeElement.getAttribute('tabindex')).toBe('-1');
       });
 
+
+     it('should clear the active item in key manager when the last focused chip is destroyed', fakeAsync(() => {
+      const fixture = createComponent(StandardChipGrid);
+      fixture.detectChanges();
+      
+      // Focus a chip
+      chips.first.focus();
+      fixture.detectChanges();
+  
+      // Remove ALL chips
+      fixture.componentInstance.foods = []; // Clear the bound data array
+      fixture.detectChanges();
+      flush();
+  
+      // Verify key manager is reset to prevent stale references
+      expect(chipGridInstance._keyManager.activeItemIndex).toBe(-1);
+    }));
+  
+  
       describe('on chip destroy', () => {
         it('should focus the next item', () => {
           const fixture = createComponent(StandardChipGrid);

src/material/chips/chip-grid.ts

@@ -492,6 +492,21 @@ export class MatChipGrid
     this.stateChanges.next();
   }
 
+   protected override _redirectDestroyedChipFocus() {
+    if (this._lastDestroyedFocusedChipIndex === null) {
+      return;
+    }
+
+    super._redirectDestroyedChipFocus();
+
+    // If there are no chips left, or the set focuses the input,
+    // clear the active item silently to prevent stale references.
+    if (!this._chips.length ||
+        (this._chips.length === 1 && this._chips.first.disabled)) {
+      this._keyManager.updateActiveItem(-1);
+    }
+  }
+
   _focusLastChip() {
     if (this._chips.length) {
       this._chips.last.focus();

src/material/chips/chip-set.ts

@@ -53,7 +53,7 @@ export class MatChipSet implements AfterViewInit, OnDestroy {
   private _dir = inject(Directionality, {optional: true});
 
   /** Index of the last destroyed chip that had focus. */
-  private _lastDestroyedFocusedChipIndex: number | null = null;
+  protected _lastDestroyedFocusedChipIndex: number | null = null;
 
   /** Used to manage focus within the chip list. */
   protected _keyManager!: FocusKeyManager<MatChipAction>;
@@ -310,7 +310,7 @@ export class MatChipSet implements AfterViewInit, OnDestroy {
    * Finds the next appropriate chip to move focus to,
    * if the currently-focused chip is destroyed.
    */
-  private _redirectDestroyedChipFocus() {
+  protected _redirectDestroyedChipFocus() {
     if (this._lastDestroyedFocusedChipIndex == null) {
       return;
     }

src/material/chips/chip.ts

@@ -298,12 +298,12 @@ export class MatChip implements OnInit, AfterViewInit, AfterContentInit, DoCheck
   }
 
   ngOnDestroy() {
-    this._focusMonitor.stopMonitoring(this._elementRef);
-    this._rippleLoader?.destroyRipple(this._elementRef.nativeElement);
-    this._actionChanges?.unsubscribe();
-    this.destroyed.emit({chip: this});
-    this.destroyed.complete();
-  }
+      this.destroyed.emit({chip: this});
+      this.destroyed.complete();
+      this._focusMonitor.stopMonitoring(this._elementRef);
+      this._rippleLoader?.destroyRipple(this._elementRef.nativeElement);
+      this._actionChanges?.unsubscribe();
+    }
 
   /**
    * Allows for programmatic removal of the chip.