Populate password into mojo api.

ash/login/ui/login_auth_user_view.cc

 // Copyright 2017 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 "ash/login/ui/login_auth_user_view.h"
 
 #include "ash/login/lock_screen_controller.h"
 #include "ash/login/ui/lock_screen.h"
 #include "ash/login/ui/login_display_style.h"
 #include "ash/login/ui/login_password_view.h"
 #include "ash/login/ui/login_pin_view.h"
 #include "ash/login/ui/login_user_view.h"
 #include "ash/shell.h"
+#include "base/strings/utf_string_conversions.h"
 #include "components/user_manager/user.h"
 #include "ui/views/layout/box_layout.h"
 #include "ui/views/view.h"
 
 namespace ash {
 namespace {
 
 const char* kLoginAuthUserViewClassName = "LoginAuthUserView";
 
 // Distance between the username label and the password textfield.
@@ skipping 89 matching lines @@
   gfx::Size size = views::View::CalculatePreferredSize();
   // Make sure we are at least as big as the user view. If we do not do this the
   // view will be below minimum size when no auth methods are displayed.
   size.SetToMax(user_view_->GetPreferredSize());
   return size;
 }
 
 void LoginAuthUserView::OnAuthSubmit(bool is_pin,
                                      const base::string16& password) {
   Shell::Get()->lock_screen_controller()->AuthenticateUser(
-      current_user_, std::string(), is_pin,
+      current_user_, UTF16ToUTF8(password), is_pin,
       base::BindOnce([](OnAuthCallback on_auth,
                         bool auth_success) { on_auth.Run(auth_success); },
                      on_auth_));
 }
 
 }  // namespace ash