Generate all runtime files from dart.

lib/runtime/dart/_js_helper.js

Index: lib/runtime/dart/_js_helper.js
diff --git a/lib/runtime/dart/_js_helper.js b/lib/runtime/dart/_js_helper.js
index 9c0b80121381bb158fc0386fffd91314bdd693be..4a70d0778c4fad0f806c0184d2a99bbd508eb9cd 100644
--- a/lib/runtime/dart/_js_helper.js
+++ b/lib/runtime/dart/_js_helper.js
@@ -1,11 +1,12 @@
 dart_library.library('dart/_js_helper', null, /* Imports */[
-  "dart/_runtime",
+  'dart/_runtime',
   'dart/core',
   'dart/collection',
+  'dart/_utils',
   'dart/_interceptors',
   'dart/_foreign_helper'
 ], /* Lazy imports */[
-], function(exports, dart, core, collection, _interceptors, _foreign_helper) {
+], function(exports, dart, core, collection, utils, _interceptors, _foreign_helper) {
   'use strict';
   let dartx = dart.dartx;
   class NoThrows extends core.Object {
@@ -516,12 +517,12 @@ dart_library.library('dart/_js_helper', null, /* Imports */[
   }
   dart.fn(getRuntimeType, core.Type, [dart.dynamic]);
   function getIndex(array, index) {
-    dart.assert(isJsArray(array));
+    utils.assert(isJsArray(array));
     return array[index];
   }
   dart.fn(getIndex, dart.dynamic, [dart.dynamic, core.int]);
   function getLength(array) {
-    dart.assert(isJsArray(array));
+    utils.assert(isJsArray(array));
     return array.length;
   }
   dart.fn(getLength, core.int, [dart.dynamic]);