Use the Mojo StubBindings interface correctly in WebUSB LayoutTests.

mojo/public/js/connection.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 define("mojo/public/js/connection", [
   "mojo/public/js/bindings",
   "mojo/public/js/connector",
   "mojo/public/js/core",
   "mojo/public/js/router",
 ], function(bindings, connector, core, router) {
 
   var Router = router.Router;
   var EmptyProxy = bindings.EmptyProxy;
   var EmptyStub = bindings.EmptyStub;
   var ProxyBindings = bindings.ProxyBindings;
   var StubBindings = bindings.StubBindings;
   var TestConnector = connector.TestConnector;
   var TestRouter = router.TestRouter;
 
   // TODO(hansmuller): the proxy receiver_ property should be receiver$
 
   function BaseConnection(localStub, remoteProxy, router) {
     this.router_ = router;
     this.local = localStub;
     this.remote = remoteProxy;
 
     this.router_.setIncomingReceiver(localStub);
+    this.router_.setErrorHandler(() => {
+      if (StubBindings(this.local) &&
+          StubBindings(this.local).connectionErrorHandler)
+        StubBindings(this.local).connectionErrorHandler();
+    });
     if (this.remote)
       this.remote.receiver_ = router;
 
     // Validate incoming messages: remote responses and local requests.
     var validateRequest = localStub && localStub.validator;
     var validateResponse = remoteProxy && remoteProxy.validator;
     var payloadValidators = [];
     if (validateRequest)
       payloadValidators.push(validateRequest);
     if (validateResponse)
@@ skipping 108 matching lines @@
   var exports = {};
   exports.Connection = Connection;
   exports.TestConnection = TestConnection;
 
   exports.bindProxy = bindProxy;
   exports.bindImpl = bindImpl;
   exports.bindHandleToProxy = bindHandleToProxy;
   exports.bindHandleToStub = bindHandleToStub;
   return exports;
 });