Auto merge of #9352 - mattkuo:cleanup-private-types, r=nox

Convert private types to public

fixes #9347

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/9352)
<!-- Reviewable:end -->

components/gfx/platform/freetype/font_context.rs

@@ -18,7 +18,7 @@ use util::mem::{HeapSizeOf, heap_size_of};
 // We pass a |User| struct -- via an opaque |void*| -- to FreeType each time a new instance is
 // created. FreeType passes it back to the ft_alloc/ft_realloc/ft_free callbacks. We use it to
 // record the memory usage of each FreeType instance.
-struct User {
+pub struct User {
     size: usize,
 }