fix #43, remove => workaround

lib/runtime/dart/_runtime.js

 dart_library.library('dart/_runtime', null, /* Imports */[
 ], /* Lazy imports */[
   'dart/core',
   'dart/_interceptors',
   'dart/_js_helper',
   'dart/async',
   'dart/collection'
 ], function(exports, core, _interceptors, _js_helper, async, collection) {
   'use strict';
   function mixin(base, ...mixins) {
@@ skipping 256 matching lines @@
   }
   const _AsyncStarStreamController = class _AsyncStarStreamController {
     constructor(generator, T, args) {
       this.isAdding = false;
       this.isWaiting = false;
       this.isScheduled = false;
       this.isSuspendedAtYield = false;
       this.canceler = null;
       this.iterator = generator(this, ...args)[Symbol.iterator]();
       this.controller = getGenericClass(async.StreamController)(T).new({
-        onListen: (() => this.scheduleGenerator()).bind(this),
-        onResume: (() => this.onResume()).bind(this),
-        onCancel: (() => this.onCancel()).bind(this)
+        onListen: () => this.scheduleGenerator(),
+        onResume: () => this.onResume(),
+        onCancel: () => this.onCancel()
       });
     }
     onResume() {
       if (this.isSuspendedAtYield) {
         this.scheduleGenerator();
       }
     }
     onCancel() {
       if (this.controller.isClosed) {
         return null;
       }
       if (this.canceler == null) {
         this.canceler = async.Completer.new();
         this.scheduleGenerator();
       }
       return this.canceler.future;
     }
     close() {
       if (this.canceler != null && !this.canceler.isCompleted) {
         this.canceler.complete();
       }
       this.controller.close();
     }
     scheduleGenerator() {
       if (this.isScheduled || this.controller.isPaused || this.isAdding || this.isWaiting) {
         return;
       }
       this.isScheduled = true;
-      async.scheduleMicrotask((() => this.runBody()).bind(this));
+      async.scheduleMicrotask(() => this.runBody());
     }
     runBody(opt_awaitValue) {
       this.isScheduled = false;
       this.isSuspendedAtYield = false;
       this.isWaiting = false;
       let iter;
       try {
         iter = this.iterator.next(opt_awaitValue);
       } catch (e) {
         this.addError(e, stackTrace(e));
         this.close();
         return;
       }
 
       if (iter.done) {
         this.close();
         return;
       }
       if (this.isSuspendedAtYield || this.isAdding) return;
       this.isWaiting = true;
       let future = iter.value;
       if (!instanceOf(future, getGenericClass(async.Future))) {
         future = async.Future.value(future);
       }
-      return future.then((x => this.runBody(x)).bind(this), {
-        onError: ((e, s) => this.throwError(e, s)).bind(this)
+      return future.then(x => this.runBody(x), {
+        onError: (e, s) => this.throwError(e, s)
       });
     }
     add(event) {
       if (!this.controller.hasListener) return true;
       this.controller.add(event);
       this.scheduleGenerator();
       this.isSuspendedAtYield = true;
       return false;
     }
     addStream(stream) {
       if (!this.controller.hasListener) return true;
       this.isAdding = true;
-      this.controller.addStream(stream, {cancelOnError: false}).then((() => {
+      this.controller.addStream(stream, {cancelOnError: false}).then(() => {
         this.isAdding = false;
         this.scheduleGenerator();
-      }).bind(this), {
-        onError: ((e, s) => this.throwError(e, s)).bind(this)
+      }, {
+        onError: (e, s) => this.throwError(e, s)
       });
     }
     throwError(error, stackTrace) {
       try {
         this.iterator.throw(error);
       } catch (e) {
         this.addError(e, stackTrace);
       }
 
     }
@@ skipping 932 matching lines @@
   exports.copyProperties = copyProperties;
   exports.export = export_;
   exports.defineLazyClass = defineLazyClass;
   exports.defineLazyProperties = defineLazyProperties;
   exports.defineLazyClassGeneric = defineLazyClassGeneric;
   exports.as = as_;
   exports.is = is_;
   exports.global = global_;
   exports.JsSymbol = JsSymbol;
 });