fuse List and js Array together and a few other misc fixes.

lib/runtime/dart_runtime.js

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 var dart, _js_helper;
 (function (dart) {
   'use strict';
 
   let defineProperty = Object.defineProperty;
   let getOwnPropertyDescriptor = Object.getOwnPropertyDescriptor;
   let getOwnPropertyNames = Object.getOwnPropertyNames;
+  let getOwnPropertySymbols = Object.getOwnPropertySymbols;
 
   // Adapted from Angular.js
   let FN_ARGS = /^function\s*[^\(]*\(\s*([^\)]*)\)/m;
   let FN_ARG_SPLIT = /,/;
   let FN_ARG = /^\s*(_?)(\S+?)\1\s*$/;
   let STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;
 
   function formalParameterList(fn) {
     let fnText,argDecl;
     let args=[];
@@ skipping 585 matching lines @@
   // TODO(jmesserly): these are identical, but this makes it easier to grep for.
   dart.defineLazyClass = defineLazy;
   dart.defineLazyProperties = defineLazy;
   dart.defineLazyClassGeneric = defineLazyProperty;
 
   /**
    * Copy properties from source to destination object.
    * This operation is commonly called `mixin` in JS.
    */
   function copyProperties(to, from) {
-    let names = getOwnPropertyNames(from);
-    for (let i = 0; i < names.length; i++) {
-      let name = names[i];
-      defineProperty(to, name, getOwnPropertyDescriptor(from, name));
+    function copyPropertiesHelper(names) {
+      for (let i = 0; i < names.length; i++) {
+        let name = names[i];
+        defineProperty(to, name, getOwnPropertyDescriptor(from, name));
+      }
     }
+    copyPropertiesHelper(getOwnPropertyNames(from));
+    copyPropertiesHelper(getOwnPropertySymbols(from));
     return to;
   }
   dart.copyProperties = copyProperties;
 
   /**
    * This is called whenever a derived class needs to introduce a new field,
    * shadowing a field or getter/setter pair on its parent.
    *
    * This is important because otherwise, trying to read or write the field
    * would end up calling the getter or setter, and one of those might not even
@@ skipping 172 matching lines @@
   dart.void = { toString() { return 'void'; } };
   dart.bottom = { toString() { return 'bottom'; } };
 
   dart.JsSymbol = Symbol;
 
   // TODO(jmesserly): hack to bootstrap the SDK
   _js_helper = _js_helper || {};
   _js_helper.checkNum = notNull;
 
 })(dart || (dart = {}));