feat(compiler-cli): lower metadata useValue and data literal fields (#18905)

With this commit the compiler will "lower" expressions into exported
variables for values the compiler does not need to know statically
in order to be able to generate a factory. For example:

```
  providers: [{provider: 'token', useValue: calculated()}]
```

produced an error as the expression `calculated()` is not supported
by the compiler because `calculated` is not a
[known function](https://angular.io/guide/metadata#annotationsdecorators)

With this commit this is rewritten, during emit of the .js file, into
something like:

```
export var ɵ0 = calculated();

  ...

  provdiers: [{provider: 'token', useValue: ɵ0}]
```

The compiler then will now generate a reference to the exported `ɵ0`
instead of failing to evaluate `calculated()`.

PR Close #18905

packages/compiler-cli/test/diagnostics/check_types_spec.ts

@@ -12,6 +12,7 @@ import * as ts from 'typescript';
 
 import {TypeChecker} from '../../src/diagnostics/check_types';
 import {Diagnostic} from '../../src/transformers/api';
+import {LowerMetadataCache} from '../../src/transformers/lower_expressions';
 
 function compile(
     rootDirs: MockData, options: AotCompilerOptions = {},
@@ -19,7 +20,7 @@ function compile(
   const rootDirArr = toMockFileArray(rootDirs);
   const scriptNames = rootDirArr.map(entry => entry.fileName).filter(isSource);
   const host = new MockCompilerHost(scriptNames, arrayToMockDir(rootDirArr));
-  const aotHost = new MockAotCompilerHost(host);
+  const aotHost = new MockAotCompilerHost(host, new LowerMetadataCache({}));
   const tsSettings = {...settings, ...tsOptions};
   const program = ts.createProgram(host.scriptNames.slice(0), tsSettings, host);
   const ngChecker = new TypeChecker(program, tsSettings, host, aotHost, options);
@@ -80,6 +81,12 @@ describe('ng type checker', () => {
     it('should accept a safe property access of a nullable field reference of a method result',
        () => { a('{{getMaybePerson()?.name}}'); });
   });
+
+  describe('with lowered expressions', () => {
+    it('should not report lowered expressions as errors', () => {
+      expectNoDiagnostics(compile([angularFiles, LOWERING_QUICKSTART]));
+    });
+  });
 });
 
 function appComponentSource(template: string): string {
@@ -134,8 +141,38 @@ const QUICKSTART: MockDirectory = {
   }
 };
 
+const LOWERING_QUICKSTART: MockDirectory = {
+  quickstart: {
+    app: {
+      'app.component.ts': appComponentSource('<h1>Hello {{name}}</h1>'),
+      'app.module.ts': `
+        import { NgModule, Component }      from '@angular/core';
+        import { toString }      from './utils';
+
+        import { AppComponent }  from './app.component';
+
+        class Foo {}
+
+        @Component({
+          template: '',
+          providers: [
+            {provide: 'someToken', useFactory: () => new Foo()}
+          ]
+        })
+        export class Bar {}
+
+        @NgModule({
+          declarations: [ AppComponent, Bar ],
+          bootstrap:    [ AppComponent ]
+        })
+        export class AppModule { }
+      `
+    }
+  }
+};
+
 function expectNoDiagnostics(diagnostics: Diagnostic[]) {
   if (diagnostics && diagnostics.length) {
     throw new Error(diagnostics.map(d => `${d.span}: ${d.message}`).join('\n'));
   }
-}
+}