fix(tsickle): support ctorParams in function closure (#12876)

See https://github.com/angular/tsickle/issues/261 for context.

modules/@angular/core/src/reflection/reflection_capabilities.ts

@@ -56,8 +56,12 @@ export class ReflectionCapabilities implements PlatformReflectionCapabilities {
     }
 
     // API of tsickle for lowering decorators to properties on the class.
-    if ((<any>type).ctorParameters) {
-      const ctorParameters = (<any>type).ctorParameters;
+    const tsickleCtorParams = (<any>type).ctorParameters;
+    if (tsickleCtorParams) {
+      // Newer tsickle uses a function closure
+      // Retain the non-function case for compatibility with older tsickle
+      const ctorParameters =
+          typeof tsickleCtorParams === 'function' ? tsickleCtorParams() : tsickleCtorParams;
       const paramTypes = ctorParameters.map((ctorParam: any) => ctorParam && ctorParam.type);
       const paramAnnotations = ctorParameters.map(
           (ctorParam: any) =>

modules/@angular/core/test/reflection/reflector_spec.ts

@@ -89,6 +89,25 @@ export function main() {
         const p = reflector.parameters(ClassWithoutDecorators);
         expect(p.length).toEqual(2);
       });
+
+      // See https://github.com/angular/tsickle/issues/261
+      it('should read forwardRef down-leveled type', () => {
+        class Dep {}
+        class ForwardLegacy {
+          constructor(d: Dep) {}
+          // Older tsickle had a bug: wrote a forward reference
+          static ctorParameters = [{type: Dep}];
+        }
+        expect(reflector.parameters(ForwardLegacy)).toEqual([[Dep]]);
+        class Forward {
+          constructor(d: Dep) {}
+          // Newer tsickle generates a functionClosure
+          static ctorParameters = () => [{type: ForwardDep}];
+        }
+        class ForwardDep {}
+        expect(reflector.parameters(Forward)).toEqual([[ForwardDep]]);
+      });
+
     });
 
     describe('propMetadata', () => {