fixes #157, renaming local library identifiers if needed.

lib/runtime/dart/collection.js

Index: lib/runtime/dart/collection.js
diff --git a/lib/runtime/dart/collection.js b/lib/runtime/dart/collection.js
index ec36746c9f81c883c9d3504cbe58ac6520a6fbb1..3ae2a6db9b02e36058ac1d67962f8a4c80913cf4 100644
--- a/lib/runtime/dart/collection.js
+++ b/lib/runtime/dart/collection.js
@@ -1,5 +1,9 @@
-var collection;
-(function(exports) {
+var collection = dart.defineLibrary(collection, {});
+var _internal = dart.import(_internal);
+var core = dart.lazyImport(core);
+var _js_helper = dart.import(_js_helper);
+var math = dart.import(math);
+(function(exports, _internal, core, _js_helper, math) {
   'use strict';
   let _source = Symbol('_source');
   let UnmodifiableListView$ = dart.generic(function(E) {
@@ -5198,4 +5202,4 @@ var collection;
   exports.LinkedHashSetCell = LinkedHashSetCell;
   exports.LinkedHashSetIterator$ = LinkedHashSetIterator$;
   exports.LinkedHashSetIterator = LinkedHashSetIterator;
-})(collection || (collection = {}));
+})(collection, _internal, core, _js_helper, math);