bug(transpiler): Support optional arguments in annotations.

Clean-up: move annotaitons out of fixtures/annotations, since we have
the @CONST annotation in the transpiler already.

tools/transpiler/spec/annotations_spec.js

@@ -1,9 +1,25 @@
 import {describe, it, expect} from 'test_lib/test_lib';
-import {Provide, readFirstAnnotation} from './fixtures/annotations';
+import {readFirstAnnotation} from './fixtures/annotations';
+import {CONST} from 'facade/lang';
 
 class Inject {}
 class Bar {}
 
+class Provide {
+  @CONST()
+  constructor(token) {
+    this.token = token;
+  }
+}
+
+class AnnotateMe {
+  @CONST()
+  constructor({maybe = 'default'} = {}) {
+    this.maybe = maybe;
+  }
+}
+
+
 @Provide('Foo')
 class Foo {
   @Inject
@@ -13,6 +29,12 @@ class Foo {
 @Provide(Foo)
 function baz() {}
 
+@AnnotateMe()
+class A {}
+
+@AnnotateMe({maybe: 'yes'})
+class B {}
+
 function annotatedParams(@Inject(Foo) f, @Inject(Bar) b) {}
 
 export function main() {
@@ -22,5 +44,10 @@ export function main() {
       var clazz = readFirstAnnotation(Foo);
       expect(clazz instanceof Provide).toBe(true);
     });
+
+    it('should work with named arguments', function() {
+      expect(readFirstAnnotation(A).maybe).toBe('default');
+      expect(readFirstAnnotation(B).maybe).toBe('yes');
+    });
   });
 }

tools/transpiler/spec/fixtures/annotations.dart

@@ -1,20 +1,5 @@
 import 'dart:mirrors';
 
-// This class is not generated,
-// but should be in the future.
-//
-// Problems:
-// - Dart requires annotations to be const (which makes sense).
-//   Right now, I can't describe that in ES6.
-class Provide {
-  final token;
-  const Provide(this.token);
-}
-
-class CONST {
-  const CONST();
-}
-
 // TODO: this api does not yet return an array as we don't have
 // a nice array wrapper for Dart
 readFirstAnnotation(clazz) {

tools/transpiler/spec/fixtures/annotations.es6

@@ -1,18 +1,3 @@
-// This class is not generated,
-// but should be in the future.
-//
-// Problems:
-// - Dart requires annotations to be const (which makes sense).
-//   Right now, I can't describe that in ES6.
-export class Provide {
-  constructor(token) {
-    this.token = token;
-  }
-}
-
-export class CONST {
-}
-
 // TODO: this api does not yet return an array as we don't have
 // a nice array wrapper for Dart
 export function readFirstAnnotation(clazz) {

tools/transpiler/src/codegeneration/NamedParamsTransformer.js

@@ -48,6 +48,12 @@ export class NamedParamsTransformer extends ParseTreeTransformer {
     return tree;
   }
 
+  transformAnnotation(tree) {
+    tree = super.transformAnnotation(tree);
+    if (tree.args) this._handleNamedParams(tree);
+    return tree;
+  }
+
   _handleNamedParams(tree) {
     if (this._isLastArgAnNonEmptyObjectLiteral(tree) &&
       ! this._isLastArgObjectLiteralWithQuotedKeys(tree)) {