fixes #168, dart:js implementation with a test

tool/input_sdk/private/foreign_helper.dart

Index: tool/input_sdk/private/foreign_helper.dart
diff --git a/tool/input_sdk/private/foreign_helper.dart b/tool/input_sdk/private/foreign_helper.dart
index 9eb15578671175d537c8cd4d803057abeebae978..468e640bcc465022f9e8fb907c5cf75c78cca4b2 100644
--- a/tool/input_sdk/private/foreign_helper.dart
+++ b/tool/input_sdk/private/foreign_helper.dart
@@ -127,28 +127,6 @@ abstract class IsolateContext {
 JS_CALL_IN_ISOLATE(isolate, Function function) {}
 
 /**
- * Converts the Dart closure [function] into a JavaScript closure.
- *
- * Warning: This is no different from [RAW_DART_FUNCTION_REF] which means care
- * must be taken to store the current isolate.
- */
-DART_CLOSURE_TO_JS(Function function) {}
-
-/**
- * Returns a raw reference to the JavaScript function which implements
- * [function].
- *
- * Warning: this is dangerous, you should probably use
- * [DART_CLOSURE_TO_JS] instead. The returned object is not a valid
- * Dart closure, does not store the isolate context or arity.
- *
- * A valid example of where this can be used is as the second argument
- * to V8's Error.captureStackTrace. See
- * https://code.google.com/p/v8/wiki/JavaScriptStackTraceApi.
- */
-RAW_DART_FUNCTION_REF(Function function) {}
-
-/**
  * Sets the current isolate to [isolate].
  */
 void JS_SET_CURRENT_ISOLATE(isolate) {}