fixes #157, renaming local library identifiers if needed.

lib/runtime/dart/_interceptors.js

-var _interceptors;
-(function(exports) {
+var _interceptors, core, _js_helper, _internal, _foreign_helper, _js_embedded_names;

[vsm, 2015/05/05 22:01:18]

It might be more readable to just list these out line by line.  E.g.,:

var _js_helper = _js_helper || {};

Alternatively,

var core = dart.required(core); // Asserts core is loaded already
var _js_helper = dart.lazy(_js_helper); // Defined if needed.

[Jennifer Messerly, 2015/05/05 22:04:44]

sounds good! yeah, almost did something like that but wasn't sure how much to
change, this is exactly the nudge I needed :). Really like the dart.required
assertion idea.

+(function(exports, core, _js_helper, _internal, _foreign_helper, _js_embedded_names) {
   'use strict';
   let JSArray = Array;
   let JSMutableArray$ = dart.generic(function(E) {
     class JSMutableArray extends JSArray$(E) {
       JSMutableArray() {
         super.JSArray();
       }
     }
     JSMutableArray[dart.implements] = () => [JSMutableIndexable];
     return JSMutableArray;
@@ skipping 1066 matching lines @@
   exports.findConstructorForNativeSubclassType = findConstructorForNativeSubclassType;
   exports.findInterceptorForType = findInterceptorForType;
   exports.JSBool = JSBool;
   exports.JSNull = JSNull;
   exports.JSIndexable = JSIndexable;
   exports.JSMutableIndexable = JSMutableIndexable;
   exports.JSObject = JSObject;
   exports.JavaScriptObject = JavaScriptObject;
   exports.PlainJavaScriptObject = PlainJavaScriptObject;
   exports.UnknownJavaScriptObject = UnknownJavaScriptObject;
-})(_interceptors || (_interceptors = {}));
+})(_interceptors || (_interceptors = {}), core, _js_helper || (_js_helper = {}), _internal, _foreign_helper, _js_embedded_names);