Change mojo enums to be scoped enums in the generated C++ bindings.

mojo/services/network/network_service_delegate.cc

Index: mojo/services/network/network_service_delegate.cc
diff --git a/mojo/services/network/network_service_delegate.cc b/mojo/services/network/network_service_delegate.cc
index fff5950744a8a76e4816162e1cc40fe4d186744d..74388f1b78403dccefae494195dc77956bbf17b9 100644
--- a/mojo/services/network/network_service_delegate.cc
+++ b/mojo/services/network/network_service_delegate.cc
@@ -101,7 +101,7 @@ void NetworkServiceDelegate::Initialize(ApplicationImpl* app) {
   filesystem::FileSystemClientPtr client;
   binding_.Bind(GetProxy(&client));
 
-  filesystem::FileError error = filesystem::FILE_ERROR_FAILED;
+  filesystem::FileError error = filesystem::FileError::FAILED;
   filesystem::DirectoryPtr directory;
   files_->OpenFileSystem("origin", GetProxy(&directory), std::move(client),
                          Capture(&error));