mash: Fix crash in browser driver.

BUG=579645
R=yzshen@chromium.org
TBR=sky@chromium.org

Review URL: https://codereview.chromium.org/1617893003

Cr-Commit-Position: refs/heads/master@{#370753}

mash/browser_driver/browser_driver_application_delegate.cc

@@ -84,12 +84,12 @@ void BrowserDriverApplicationDelegate::AddAccelerators() {
 
   if (binding_.is_bound())
     binding_.Unbind();
+  registrar->SetHandler(binding_.CreateInterfacePtrAndBind());
   // 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(binding_.CreateInterfacePtrAndBind());
 
   for (const AcceleratorSpec& spec : g_spec) {
     registrar->AddAccelerator(