fixes #168, dart:js implementation with a test

test/codegen/expect/html_input.html

Index: test/codegen/expect/html_input.html
diff --git a/test/codegen/expect/html_input.html b/test/codegen/expect/html_input.html
index b1ab38df0cecef68f7b8500ea60007fb3e3ea735..56654cb1bc5eefd46c66eda0e9bf303aabf3b6dd 100644
--- a/test/codegen/expect/html_input.html
+++ b/test/codegen/expect/html_input.html
@@ -25,6 +25,7 @@
 <script src="dev_compiler/runtime/dart/convert.js"></script>
 <script src="dev_compiler/runtime/dart/mirrors.js"></script>
 <script src="dev_compiler/runtime/dart/_js_mirrors.js"></script>
+<script src="dev_compiler/runtime/dart/js.js"></script>
 <script src="dir/html_input_d.js"></script>
 <script src="dir/html_input_b.js"></script>
 <script src="dir/html_input_e.js"></script>