fix(material/checkbox): breaking changes for v20

Removes the deprecated symbols for v20 from the checkbox.

BREAKING CHANGE:
* `MAT_CHECKBOX_REQUIRED_VALIDATOR` has been removed.
* `MAT_CHECKBOX_VALUE_ACCESSOR` has been removed.
* `MatCheckboxRequiredValidator` has been removed.
* `_MatCheckboxRequiredValidatorModule` has been removed.

Author: crisbeto

src/material/checkbox/checkbox-required-validator.ts

@@ -59,16 +59,6 @@ export enum TransitionCheckState {
   Indeterminate,
 }
 
-/**
- * @deprecated Will stop being exported.
- * @breaking-change 19.0.0
- */
-export const MAT_CHECKBOX_CONTROL_VALUE_ACCESSOR: any = {
-  provide: NG_VALUE_ACCESSOR,
-  useExisting: forwardRef(() => MatCheckbox),
-  multi: true,
-};
-
 /** Change event object emitted by checkbox. */
 export class MatCheckboxChange {
   /** The source checkbox of the event. */
@@ -99,7 +89,11 @@ const defaults = MAT_CHECKBOX_DEFAULT_OPTIONS_FACTORY();
     '[class]': 'color ? "mat-" + color : "mat-accent"',
   },
   providers: [
-    MAT_CHECKBOX_CONTROL_VALUE_ACCESSOR,
+    {
+      provide: NG_VALUE_ACCESSOR,
+      useExisting: forwardRef(() => MatCheckbox),
+      multi: true,
+    },
     {
       provide: NG_VALIDATORS,
       useExisting: MatCheckbox,

src/material/checkbox/checkbox.ts

@@ -9,17 +9,6 @@
 import {NgModule} from '@angular/core';
 import {MatCommonModule} from '@angular/material/core';
 import {MatCheckbox} from './checkbox';
-import {MatCheckboxRequiredValidator} from './checkbox-required-validator';
-
-/**
- * @deprecated No longer used, `MatCheckbox` implements required validation directly.
- * @breaking-change 19.0.0
- */
-@NgModule({
-  imports: [MatCheckboxRequiredValidator],
-  exports: [MatCheckboxRequiredValidator],
-})
-export class _MatCheckboxRequiredValidatorModule {}
 
 @NgModule({
   imports: [MatCheckbox, MatCommonModule],

src/material/checkbox/module.ts

@@ -9,4 +9,3 @@
 export * from './checkbox';
 export * from './checkbox-config';
 export * from './module';
-export * from './checkbox-required-validator';

src/material/checkbox/public-api.ts

@@ -6,33 +6,25 @@
 
 import { AbstractControl } from '@angular/forms';
 import { AfterViewInit } from '@angular/core';
-import { CheckboxRequiredValidator } from '@angular/forms';
 import { ControlValueAccessor } from '@angular/forms';
 import { ElementRef } from '@angular/core';
 import { EventEmitter } from '@angular/core';
 import { FocusableOption } from '@angular/cdk/a11y';
 import * as i0 from '@angular/core';
-import * as i3 from '@angular/material/core';
+import * as i2 from '@angular/material/core';
 import { InjectionToken } from '@angular/core';
 import { OnChanges } from '@angular/core';
-import { Provider } from '@angular/core';
 import { SimpleChanges } from '@angular/core';
 import { ThemePalette } from '@angular/material/core';
 import { ValidationErrors } from '@angular/forms';
 import { Validator } from '@angular/forms';
 
-// @public @deprecated (undocumented)
-export const MAT_CHECKBOX_CONTROL_VALUE_ACCESSOR: any;
-
 // @public
 export const MAT_CHECKBOX_DEFAULT_OPTIONS: InjectionToken<MatCheckboxDefaultOptions>;
 
 // @public
 export function MAT_CHECKBOX_DEFAULT_OPTIONS_FACTORY(): MatCheckboxDefaultOptions;
 
-// @public @deprecated (undocumented)
-export const MAT_CHECKBOX_REQUIRED_VALIDATOR: Provider;
-
 // @public (undocumented)
 export class MatCheckbox implements AfterViewInit, OnChanges, ControlValueAccessor, Validator, FocusableOption {
     constructor(...args: unknown[]);
@@ -154,25 +146,7 @@ export class MatCheckboxModule {
     // (undocumented)
     static ɵinj: i0.ɵɵInjectorDeclaration<MatCheckboxModule>;
     // (undocumented)
-    static ɵmod: i0.ɵɵNgModuleDeclaration<MatCheckboxModule, never, [typeof i2.MatCheckbox, typeof i3.MatCommonModule], [typeof i2.MatCheckbox, typeof i3.MatCommonModule]>;
-}
-
-// @public @deprecated
-export class MatCheckboxRequiredValidator extends CheckboxRequiredValidator {
-    // (undocumented)
-    static ɵdir: i0.ɵɵDirectiveDeclaration<MatCheckboxRequiredValidator, "mat-checkbox[required][formControlName],             mat-checkbox[required][formControl], mat-checkbox[required][ngModel]", never, {}, {}, never, never, true, never>;
-    // (undocumented)
-    static ɵfac: i0.ɵɵFactoryDeclaration<MatCheckboxRequiredValidator, never>;
-}
-
-// @public @deprecated (undocumented)
-export class _MatCheckboxRequiredValidatorModule {
-    // (undocumented)
-    static ɵfac: i0.ɵɵFactoryDeclaration<_MatCheckboxRequiredValidatorModule, never>;
-    // (undocumented)
-    static ɵinj: i0.ɵɵInjectorDeclaration<_MatCheckboxRequiredValidatorModule>;
-    // (undocumented)
-    static ɵmod: i0.ɵɵNgModuleDeclaration<_MatCheckboxRequiredValidatorModule, never, [typeof i1.MatCheckboxRequiredValidator], [typeof i1.MatCheckboxRequiredValidator]>;
+    static ɵmod: i0.ɵɵNgModuleDeclaration<MatCheckboxModule, never, [typeof i1.MatCheckbox, typeof i2.MatCommonModule], [typeof i1.MatCheckbox, typeof i2.MatCommonModule]>;
 }
 
 // @public