fix(ivy): ngcc - separate typings rendering from src rendering (#25445)

Previously the same `Renderer` was used to render typings (.d.ts)
files. But the new `UmdRenderer` is not able to render typings files
correctly.

This commit splits out the typings rendering from the src rendering.
To achieve this the previous renderers have been refactored from
sub-classes of the abstract `Renderer` class to  classes that implement
the `RenderingFormatter` interface, which are then passed to the
`Renderer` and `DtsRenderer` to modify its rendering behaviour.

Along the way a few utility interfaces and classes have been moved
around and renamed for clarity.

PR Close #25445

packages/compiler-cli/ngcc/src/rendering/esm5_rendering_formatter.ts

@@ -0,0 +1,38 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+import MagicString from 'magic-string';
+import * as ts from 'typescript';
+import {CompiledClass} from '../analysis/decoration_analyzer';
+import {getIifeBody} from '../host/esm5_host';
+import {EsmRenderingFormatter} from './esm_rendering_formatter';
+
+/**
+ * A RenderingFormatter that works with files that use ECMAScript Module `import` and `export`
+ * statements, but instead of `class` declarations it uses ES5 `function` wrappers for classes.
+ */
+export class Esm5RenderingFormatter extends EsmRenderingFormatter {
+  /**
+   * Add the definitions inside the IIFE of each decorated class
+   */
+  addDefinitions(output: MagicString, compiledClass: CompiledClass, definitions: string): void {
+    const iifeBody = getIifeBody(compiledClass.declaration);
+    if (!iifeBody) {
+      throw new Error(
+          `Compiled class declaration is not inside an IIFE: ${compiledClass.name} in ${compiledClass.declaration.getSourceFile().fileName}`);
+    }
+
+    const returnStatement = iifeBody.statements.find(ts.isReturnStatement);
+    if (!returnStatement) {
+      throw new Error(
+          `Compiled class wrapper IIFE does not have a return statement: ${compiledClass.name} in ${compiledClass.declaration.getSourceFile().fileName}`);
+    }
+
+    const insertionPoint = returnStatement.getFullStart();
+    output.appendLeft(insertionPoint, '\n' + definitions);
+  }
+}