fix: compare strings with StringWrapper.equals

Fixes https://github.com/angular/angular/issues/2458

modules/angular2/src/render/dom/events/key_events.ts

@@ -91,7 +91,7 @@ export class KeyEventsPlugin extends EventManagerPlugin {
   static eventCallback(element, shouldSupportBubble, fullKey, handler, zone) {
     return (event) => {
       var correctElement = shouldSupportBubble || event.target === element;
-      if (correctElement && KeyEventsPlugin.getEventFullKey(event) === fullKey) {
+      if (correctElement && StringWrapper.equals(KeyEventsPlugin.getEventFullKey(event), fullKey)) {
         zone.run(() => handler(event));
       }
     };