fixes #415, correct type for map literals

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 502 matching lines @@
   }
   function equals(x, y) {
     if (x == null || y == null) return x == y;
     let eq = x['=='];
     return eq ? eq.call(x, y) : x === y;
   }
   function notNull(x) {
     if (x == null) throwNullValueError();
     return x;
   }
-  function map(values) {
-    let map = collection.LinkedHashMap.new();
-    if (Array.isArray(values)) {
-      for (let i = 0, end = values.length - 1; i < end; i += 2) {
-        let key = values[i];
-        let value = values[i + 1];
-        map.set(key, value);
+  function map(values, K, V) {
+    if (K === void 0) K = null;
+    if (V === void 0) V = null;
+    return (() => {
+      if (K == null) K = dynamicR;
+      if (V == null) V = dynamicR;
+      let map = getGenericClass(collection.LinkedHashMap)(K, V).new();
+      if (Array.isArray(values)) {
+        for (let i = 0, end = values.length - 1; i < end; i += 2) {
+          let key = values[i];
+          let value = values[i + 1];
+          map.set(key, value);
+        }
+      } else if (typeof values === 'object') {
+        for (let key of getOwnPropertyNames(values)) {
+          map.set(key, values[key]);
+        }
       }
-    } else if (typeof values === 'object') {
-      for (let key of getOwnPropertyNames(values)) {
-        map.set(key, values[key]);
-      }
-    }
-    return map;
+      return map;
+    })();
   }
   function assert_(condition) {
     if (!condition) throwAssertionError();
   }
   const _stack = new WeakMap();
   function throw_(obj) {
     if (obj != null && (typeof obj == 'object' || typeof obj == 'function')) {
       _stack.set(obj, new Error());
     }
     throw obj;
@@ skipping 747 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;
 });