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

services/files/shared_impl.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 "services/files/shared_impl.h"
 
 #include <errno.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <time.h>
@@ skipping 32 matching lines @@
   file_info->atime->nanoseconds = static_cast<int32_t>(buf.st_atime_nsec);
   file_info->mtime->seconds = static_cast<int64_t>(buf.st_mtime);
   file_info->mtime->nanoseconds = static_cast<int32_t>(buf.st_mtime_nsec);
 #else
   file_info->atime->seconds = static_cast<int64_t>(buf.st_atim.tv_sec);
   file_info->atime->nanoseconds = static_cast<int32_t>(buf.st_atim.tv_nsec);
   file_info->mtime->seconds = static_cast<int64_t>(buf.st_mtim.tv_sec);
   file_info->mtime->nanoseconds = static_cast<int32_t>(buf.st_mtim.tv_nsec);
 #endif
 
-  callback.Run(ERROR_OK, file_info.Pass());
+  callback.Run(Error::OK, file_info.Pass());
 }
 
 void TouchFD(int fd,
              TimespecOrNowPtr atime,
              TimespecOrNowPtr mtime,
              const TouchFDCallback& callback) {
   DCHECK_NE(fd, -1);
 
   struct timespec times[2];
   Error error = TimespecOrNowToStandardTimespec(atime.get(), &times[0]);
-  if (error != ERROR_OK) {
+  if (error != Error::OK) {
     callback.Run(error);
     return;
   }
 
   error = TimespecOrNowToStandardTimespec(mtime.get(), &times[1]);
-  if (error != ERROR_OK) {
+  if (error != Error::OK) {
     callback.Run(error);
     return;
   }
 
   if (futimens(fd, times) != 0) {
     callback.Run(ErrnoToError(errno));
     return;
   }
 
-  callback.Run(ERROR_OK);
+  callback.Run(Error::OK);
 }
 
 }  // namespace files
 }  // namespace mojo