fixes #157, renaming local library identifiers if needed.

lib/runtime/dart/convert.js

Index: lib/runtime/dart/convert.js
diff --git a/lib/runtime/dart/convert.js b/lib/runtime/dart/convert.js
index a5ba6200032f7e8cf2e813e3793a48416f07a74a..87f66d33e91978b395918a850951d62c6982507a 100644
--- a/lib/runtime/dart/convert.js
+++ b/lib/runtime/dart/convert.js
@@ -1,5 +1,5 @@
-var convert;
-(function(exports) {
+var convert, core, async, typed_data, _internal, collection;
+(function(exports, core, async, typed_data, _internal, collection) {
   'use strict';
   let ASCII = dart.const(new AsciiCodec());
   let _ASCII_MASK = 127;
@@ -2429,4 +2429,4 @@ var convert;
   exports.Utf8Codec = Utf8Codec;
   exports.Utf8Encoder = Utf8Encoder;
   exports.Utf8Decoder = Utf8Decoder;
-})(convert || (convert = {}));
+})(convert || (convert = {}), core, async || (async = {}), typed_data || (typed_data = {}), _internal, collection);