feat: alllow specifying directives as bindings

Related to #709
Closes #1498

modules/angular2/src/core/compiler/compiler.js

@@ -1,4 +1,4 @@
-import {Injectable} from 'angular2/di';
+import {Injectable, Binding} from 'angular2/di';
 import {Type, isBlank, isPresent, BaseException, normalizeBlank, stringify} from 'angular2/src/facade/lang';
 import {Promise, PromiseWrapper} from 'angular2/src/facade/async';
 import {List, ListWrapper, Map, MapWrapper} from 'angular2/src/facade/collection';
@@ -76,9 +76,13 @@ export class Compiler {
   _bindDirective(directiveTypeOrBinding):DirectiveBinding {
     if (directiveTypeOrBinding instanceof DirectiveBinding) {
       return directiveTypeOrBinding;
+    } else if (directiveTypeOrBinding instanceof Binding) {
+      let meta = this._reader.read(directiveTypeOrBinding.token);
+      return DirectiveBinding.createFromBinding(directiveTypeOrBinding, meta.annotation);
+    } else {
+      let meta = this._reader.read(directiveTypeOrBinding);
+      return DirectiveBinding.createFromType(meta.type, meta.annotation);
     }
-    var meta = this._reader.read(directiveTypeOrBinding);
-    return DirectiveBinding.createFromType(meta.type, meta.annotation);
   }
 
   // Create a hostView as if the compiler encountered <hostcmp></hostcmp>.

modules/angular2/test/core/compiler/integration_spec.js

@@ -274,6 +274,31 @@ export function main() {
         });
       }));
 
+      it('should allow specifying directives as bindings', inject([TestBed, AsyncTestCompleter], (tb, async) => {
+        tb.overrideView(MyComp, new View({
+          template: '<child-cmp></child-cmp>',
+          directives: [bind(ChildComp).toClass(ChildComp)]
+        }));
+
+        tb.createView(MyComp, {context: ctx}).then((view) => {
+          view.detectChanges();
+
+          expect(view.rootNodes).toHaveText('hello');
+          async.done();
+        });
+      }));
+
+      it('should read directives metadata from their binding token', inject([TestBed, AsyncTestCompleter], (tb, async) => {
+        tb.overrideView(MyComp, new View({
+          template: '<div public-api><div needs-public-api></div></div>',
+          directives: [bind(PublicApi).toClass(PrivateImpl), NeedsPublicApi]
+        }));
+
+        tb.createView(MyComp, {context: ctx}).then((view) => {
+          async.done();
+        });
+      }));
+
       it('should support template directives via `<template>` elements.', inject([TestBed, AsyncTestCompleter], (tb, async) => {
         tb.overrideView(MyComp,
           new View({
@@ -1191,3 +1216,24 @@ class NeedsAttribute {
     this.fooAttribute = fooAttribute;
   }
 }
+
+@Decorator({
+  selector: '[public-api]'
+})
+class PublicApi {
+}
+
+@Decorator({
+  selector: '[private-impl]'
+})
+class PrivateImpl extends PublicApi {
+}
+
+@Decorator({
+  selector: '[needs-public-api]'
+})
+class NeedsPublicApi {
+  constructor(@Parent() api:PublicApi) {
+    expect(api instanceof PrivateImpl).toBe(true);
+  }
+}