Support some file operations in dart:io under mojo

services/files/directory_impl.cc

Index: services/files/directory_impl.cc
diff --git a/services/files/directory_impl.cc b/services/files/directory_impl.cc
index 1b17985f9635c88f7a720a3c3df9d71885f17f4d..3309cdb5adae6d2983fdf6061e238388b335cd08 100644
--- a/services/files/directory_impl.cc
+++ b/services/files/directory_impl.cc
@@ -262,7 +262,7 @@ void DirectoryImpl::OpenDirectory(const String& path,
       // Allow |EEXIST| if |kOpenFlagExclusive| is not set. Note, however, that
       // it does not guarantee that |path| is a directory.
       // TODO(vtl): Hrm, ponder if we should check that |path| is a directory.
-      if (errno != EEXIST || !(open_flags & kOpenFlagExclusive)) {
+      if ((errno != EEXIST) || (open_flags & kOpenFlagExclusive)) {
         callback.Run(ErrnoToError(errno));
         return;
       }