Reduce boilerplate needed to configure mojo::Binding

mash/browser_driver/browser_driver_application_delegate.cc

 // Copyright 2015 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.
 
 #include "mash/browser_driver/browser_driver_application_delegate.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "components/mus/public/cpp/event_matcher.h"
@@ skipping 68 matching lines @@
 }
 
 void BrowserDriverApplicationDelegate::AddAccelerators() {
   // TODO(beng): find some other way to get the window manager. I don't like
   //             having to specify it by URL because it may differ per display.
   mus::mojom::AcceleratorRegistrarPtr registrar;
   app_->ConnectToService("mojo:desktop_wm", &registrar);
 
   if (binding_.is_bound())
     binding_.Unbind();
-  mus::mojom::AcceleratorHandlerPtr handler;
-  binding_.Bind(GetProxy(&handler));
   // If the window manager restarts, the handler pipe will close and we'll need
   // to re-add our accelerators when the window manager comes back up.
   binding_.set_connection_error_handler(
       base::Bind(&BrowserDriverApplicationDelegate::AddAccelerators,
                  base::Unretained(this)));
-  registrar->SetHandler(std::move(handler));
+  registrar->SetHandler(binding_.CreateInterfacePtrAndBind());
 
   for (const AcceleratorSpec& spec : g_spec) {
     registrar->AddAccelerator(
         static_cast<uint32_t>(spec.id),
         mus::CreateKeyMatcher(spec.keyboard_code, spec.event_flags),
         base::Bind(&AssertTrue));
   }
 }
 
 }  // namespace browser_driver
 }  // namespace main