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

services/device_info/device_info.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 <cstdlib>
 
 #include "mojo/common/binding_set.h"
 #include "mojo/public/c/system/main.h"
 #include "mojo/public/cpp/application/application_connection.h"
 #include "mojo/public/cpp/application/application_delegate.h"
 #include "mojo/public/cpp/application/application_runner.h"
 #include "mojo/public/cpp/application/interface_factory.h"
 #include "mojo/services/device_info/public/interfaces/device_info.mojom.h"
 
 namespace mojo {
 namespace services {
 namespace device_info {
 
 // This is a native Mojo application which implements |DeviceInfo| interface for
 // Linux.
 class DeviceInfo : public mojo::ApplicationDelegate,
                    public mojo::DeviceInfo,
                    public mojo::InterfaceFactory<mojo::DeviceInfo> {
  public:
   // We look for the 'DISPLAY' environment variable. If present, then we assume
   // it to be a desktop, else we assume it to be a commandline
   void GetDeviceType(const GetDeviceTypeCallback& callback) override {
-    callback.Run(getenv("DISPLAY") ? DEVICE_TYPE_DESKTOP
-                                   : DEVICE_TYPE_HEADLESS);
+    callback.Run(getenv("DISPLAY") ? DeviceInfo::DeviceType::DESKTOP
+                                   : DeviceInfo::DeviceType::HEADLESS);
   }
 
   // |ApplicationDelegate| override.
   bool ConfigureIncomingConnection(
       mojo::ApplicationConnection* connection) override {
     connection->AddService<mojo::DeviceInfo>(this);
     return true;
   }
 
   // |InterfaceFactory<DeviceInfo>| implementation.
   void Create(mojo::ApplicationConnection* connection,
               mojo::InterfaceRequest<mojo::DeviceInfo> request) override {
     binding_.AddBinding(this, request.Pass());
   }
 
  private:
   mojo::BindingSet<mojo::DeviceInfo> binding_;
 };
 
 }  // namespace device_info
 }  // namespace services
 }  // namespace mojo
 
 MojoResult MojoMain(MojoHandle application_request) {
   mojo::ApplicationRunner runner(new mojo::services::device_info::DeviceInfo());
   return runner.Run(application_request);
 }