For c++, Generate enum classes instead of enum from mojom.

examples/keyboard_client/keyboard_client.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 <algorithm>
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "mojo/application/application_runner_chromium.h"
 #include "mojo/gpu/gl_texture.h"
@@ skipping 159 matching lines @@
                           nullptr);
     keyboard_sp->ConnectToService(keyboard::KeyboardService::Name_,
                                   GetProxy(&keyboard_).PassMessagePipe());
 
     keyboard_->ShowByRequest();
     keyboard_->Hide();
 
     keyboard::KeyboardClientPtr keyboard_client;
     auto request = mojo::GetProxy(&keyboard_client);
     binding_.Bind(request.Pass());
-    keyboard_->Show(keyboard_client.Pass(), keyboard::KEYBOARD_TYPE_TEXT);
+    keyboard_->Show(keyboard_client.Pass(), keyboard::KeyboardType::TEXT);
 
     mojo::ServiceProviderPtr surfaces_service_provider;
     shell_->ConnectToApplication("mojo:surfaces_service",
                                  mojo::GetProxy(&surfaces_service_provider),
                                  nullptr);
     mojo::ConnectToService(surfaces_service_provider.get(), &surface_);
     gl_context_ = mojo::GLContext::Create(shell_);
 
     surface_->CreateSurface(root_view_surface_id_);
     surface_->CreateSurface(text_view_surface_id_);
@@ skipping 203 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(KeyboardDelegate);
 };
 
 }  // namespace examples
 
 MojoResult MojoMain(MojoHandle application_request) {
   mojo::ApplicationRunnerChromium runner(new examples::KeyboardDelegate);
   return runner.Run(application_request);
 }