feat(dart/transform): Introduce @AngularEntrypoint()

modules/angular2/src/core/angular_entrypoint.ts

@@ -0,0 +1,22 @@
+import {CONST} from 'angular2/src/facade/lang';
+
+/**
+ * Marks a function or method as an Angular 2 entrypoint. Only necessary in Dart code.
+ *
+ * The optional `name` parameter will be reflected in logs when the entry point is processed.
+ *
+ * See [the wiki][] for detailed documentation.
+ * [the wiki]: https://github.com/angular/angular/wiki/Angular-2-Dart-Transformer#entry_points
+ *
+ * ## Example
+ *
+ * ```
+ * @AngularEntrypoint("name-for-debug")
+ * void main() {
+ *   bootstrap(MyComponent);
+ * }
+ */
+@CONST()
+export class AngularEntrypoint {
+  constructor(public name?: String) {}
+}