Mojo JS Bindings: Add support for closing Proxy and Stub connections

mojo/services/public/js/shell.js

Index: mojo/services/public/js/shell.js
diff --git a/mojo/services/public/js/shell.js b/mojo/services/public/js/shell.js
index d80a2e9ad57e734ec5fe41dfc03d339f3fbd7e0e..e6c2dee1fdb0a2d1e032c6220cd41f2a93d9c1dc 100644
--- a/mojo/services/public/js/shell.js
+++ b/mojo/services/public/js/shell.js
@@ -46,8 +46,7 @@ define("mojo/services/public/js/shell", [
       this.applications_.forEach(function(application, url) {
         application.close();
       });
-      // TODO(hansmuller): Use a proper API on Proxy to close.
-      core.close(this.shellProxy.handleStash);
+      ProxyBindings(this.shellProxy).close();
       this.applications_.clear();
     }
   }