mus: Remove unnecessary const from property TypeConverter templates

mash/screenlock/screenlock.cc

 // Copyright 2016 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/screenlock/screenlock.h"
 
 #include "base/macros.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/mus/public/cpp/property_type_converters.h"
 #include "mash/session/public/interfaces/session.mojom.h"
@@ skipping 77 matching lines @@
   aura_init_.reset(new views::AuraInit(connector, "views_mus_resources.pak"));
   views::WindowManagerConnection::Create(connector);
 
   views::Widget* widget = new views::Widget;
   views::Widget::InitParams params(
       views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
   params.delegate = new ScreenlockView(connector);
 
   std::map<std::string, std::vector<uint8_t>> properties;
   properties[mash::wm::mojom::kWindowContainer_Property] =
-      mojo::TypeConverter<const std::vector<uint8_t>, int32_t>::Convert(
+      mojo::ConvertTo<std::vector<uint8_t>>(
           static_cast<int32_t>(mash::wm::mojom::Container::LOGIN_WINDOWS));
   mus::Window* window =
       views::WindowManagerConnection::Get()->NewWindow(properties);
   params.native_widget = new views::NativeWidgetMus(
       widget, connector, window, mus::mojom::SurfaceType::DEFAULT);
   widget->Init(params);
   widget->Show();
 }
 
 void Screenlock::ScreenlockStateChanged(bool screen_locked) {
   if (!screen_locked)
     base::MessageLoop::current()->QuitWhenIdle();
 }
 
 }  // namespace screenlock
 }  // namespace main