feat(events): adds support for injectable angular event emitters.

Event emitters can be injected into Directives. Event emitters take over
browser events with the same name. Emitted events do not bubble. Event
emitters can be injected even if there is no corresponding callback in
the template.

Use as follows:
@Decorator(...)
class MyDec(@EventEmitter('click') clickEmitter) {
 ...
 fireClick() {
  var eventData = {...};
  this._clickEmitter(eventData);
 }
}

modules/core/test/compiler/view_spec.js

@@ -7,6 +7,7 @@ import {Component, Decorator, Template} from 'core/annotations/annotations';
 import {OnChange} from 'core/core';
 import {Lexer, Parser, ProtoChangeDetector, ChangeDetector} from 'change_detection/change_detection';
 import {TemplateConfig} from 'core/annotations/template_config';
+import {EventEmitter} from 'core/annotations/events';
 import {List, MapWrapper} from 'facade/collection';
 import {DOM, Element} from 'facade/dom';
 import {int, proxy, IMPLEMENTS} from 'facade/lang';
@@ -233,7 +234,7 @@ export function main() {
           pv.bindElement(testProtoElementInjector);
 
           var hostProtoInjector = new ProtoElementInjector(null, 0, []);
-          var hostInjector = hostProtoInjector.instantiate(null, null);
+          var hostInjector = hostProtoInjector.instantiate(null, null, null);
           var view;
           expect(() => view = pv.instantiate(hostInjector)).not.toThrow();
           expect(testProtoElementInjector.parentElementInjector).toBe(view.elementInjectors[0]);
@@ -248,7 +249,7 @@ export function main() {
           pv.bindElement(testProtoElementInjector);
 
           var hostProtoInjector = new ProtoElementInjector(null, 0, []);
-          var hostInjector = hostProtoInjector.instantiate(null, null);
+          var hostInjector = hostProtoInjector.instantiate(null, null, null);
           expect(() => pv.instantiate(hostInjector)).not.toThrow();
           expect(testProtoElementInjector.parentElementInjector).toBeNull();
           expect(testProtoElementInjector.hostElementInjector).toBe(hostInjector);
@@ -453,9 +454,30 @@ export function main() {
           createViewAndContext(createProtoView());
 
           view.dehydrate();
-          dispatchClick(view.nodes[0]);
+          expect(() => dispatchClick(view.nodes[0])).not.toThrow();
           expect(called).toEqual(0);
         });
+
+        it('should support custom event emitters', () => {
+          var pv = new ProtoView(el('<div class="ng-binding"><div></div></div>'),
+            new ProtoChangeDetector());
+          pv.bindElement(new TestProtoElementInjector(null, 0, [EventEmitterDirective]));
+          pv.bindEvent('click', parser.parseBinding('callMe(\$event)', null));
+
+          createViewAndContext(pv);
+          var dir = view.elementInjectors[0].get(EventEmitterDirective);
+
+          var dispatchedEvent = new Object();
+
+          dir.click(dispatchedEvent);
+          expect(receivedEvent).toBe(dispatchedEvent);
+          expect(called).toEqual(1);
+
+          // Should not eval the binding, because custom emitter takes over.
+          dispatchClick(view.nodes[0]);
+
+          expect(called).toEqual(1);
+        });
       });
 
       describe('react to record changes', () => {
@@ -634,6 +656,17 @@ class AnotherDirective {
   }
 }
 
+class EventEmitterDirective {
+  _clicker:Function;
+  constructor(@EventEmitter('click') clicker:Function) {
+    this._clicker = clicker;
+  }
+  click(eventData) {
+    this._clicker(eventData);
+  }
+}
+
+
 class MyEvaluationContext {
   foo:string;
   a;
@@ -652,9 +685,9 @@ class TestProtoElementInjector extends ProtoElementInjector {
     super(parent, index, bindings, firstBindingIsComponent);
   }
 
-  instantiate(parent:ElementInjector, host:ElementInjector):ElementInjector {
+  instantiate(parent:ElementInjector, host:ElementInjector, events):ElementInjector {
     this.parentElementInjector = parent;
     this.hostElementInjector = host;
-    return super.instantiate(parent, host);
+    return super.instantiate(parent, host, events);
   }
 }