feat(ivy): use i18n locale data to determine the plural form of ICU expressions (#29249)

Plural ICU expressions depend on the locale (different languages have different plural forms). Until now the locale was hard coded as `en-US`.
For compatibility reasons, if you use ivy with AOT and bootstrap your app with `bootstrapModule` then the `LOCALE_ID` token will be set automatically for ivy, which is then used to get the correct plural form.
If you use JIT, you need to define the `LOCALE_ID` provider on the module that you bootstrap.
For `TestBed` you can use either `configureTestingModule` or `overrideProvider` to define that provider.
If you don't use the compat mode and start your app with `renderComponent` you need to call `ɵsetLocaleId` manually to define the `LOCALE_ID` before bootstrap. We expect this to change once we start adding the new i18n APIs, so don't rely on this function (there's a reason why it's a private export).
PR Close #29249

packages/compiler-cli/src/ngtsc/annotations/src/ng_module.ts

@@ -6,7 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 
-import {Expression, ExternalExpr, InvokeFunctionExpr, LiteralArrayExpr, R3Identifiers, R3InjectorMetadata, R3NgModuleMetadata, R3Reference, Statement, WrappedNodeExpr, compileInjector, compileNgModule} from '@angular/compiler';
+import {Expression, ExternalExpr, InvokeFunctionExpr, LiteralArrayExpr, LiteralExpr, R3Identifiers, R3InjectorMetadata, R3NgModuleMetadata, R3Reference, Statement, WrappedNodeExpr, compileInjector, compileNgModule} from '@angular/compiler';
+import {STRING_TYPE} from '@angular/compiler/src/output/output_ast';
 import * as ts from 'typescript';
 
 import {ErrorCode, FatalDiagnosticError} from '../../diagnostics';
@@ -17,7 +18,6 @@ import {NgModuleRouteAnalyzer} from '../../routing';
 import {LocalModuleScopeRegistry, ScopeData} from '../../scope';
 import {AnalysisOutput, CompileResult, DecoratorHandler, DetectResult, HandlerPrecedence, ResolveResult} from '../../transform';
 import {getSourceFile} from '../../util/src/typescript';
-
 import {generateSetClassMetadataCall} from './metadata';
 import {ReferencesRegistry} from './references_registry';
 import {combineResolvers, findAngularDecorator, forwardRefResolver, getValidConstructorDependencies, isExpressionForwardReference, toR3Reference, unwrapExpression} from './util';
@@ -41,7 +41,7 @@ export class NgModuleDecoratorHandler implements DecoratorHandler<NgModuleAnalys
       private scopeRegistry: LocalModuleScopeRegistry,
       private referencesRegistry: ReferencesRegistry, private isCore: boolean,
       private routeAnalyzer: NgModuleRouteAnalyzer|null, private refEmitter: ReferenceEmitter,
-      private defaultImportRecorder: DefaultImportRecorder) {}
+      private defaultImportRecorder: DefaultImportRecorder, private localeId?: string) {}
 
   readonly precedence = HandlerPrecedence.PRIMARY;
 
@@ -247,7 +247,7 @@ export class NgModuleDecoratorHandler implements DecoratorHandler<NgModuleAnalys
         ngModuleStatements.push(callExpr.toStmt());
       }
     }
-    return [
+    const res: CompileResult[] = [
       {
         name: 'ngModuleDef',
         initializer: ngModuleDef.expression,
@@ -259,8 +259,19 @@ export class NgModuleDecoratorHandler implements DecoratorHandler<NgModuleAnalys
         initializer: ngInjectorDef.expression,
         statements: ngInjectorDef.statements,
         type: ngInjectorDef.type,
-      },
+      }
     ];
+
+    if (this.localeId) {
+      res.push({
+        name: 'ngLocaleIdDef',
+        initializer: new LiteralExpr(this.localeId),
+        statements: [],
+        type: STRING_TYPE
+      });
+    }
+
+    return res;
   }
 
   private _toR3Reference(

packages/compiler-cli/src/ngtsc/program.ts

@@ -447,7 +447,8 @@ export class NgtscProgram implements api.Program {
           this.options.strictInjectionParameters || false),
       new NgModuleDecoratorHandler(
           this.reflector, evaluator, scopeRegistry, referencesRegistry, this.isCore,
-          this.routeAnalyzer, this.refEmitter, this.defaultImportTracker),
+          this.routeAnalyzer, this.refEmitter, this.defaultImportTracker,
+          this.options.i18nInLocale),
       new PipeDecoratorHandler(
           this.reflector, evaluator, scopeRegistry, this.defaultImportTracker, this.isCore),
     ];