Code review comment for lp:~mhr3/unity/icon-loader-width-and-height

502 + int size = max_height < 0 ? max_width : max_height;
510 + int size = max_height < 0 ? max_width : max_height;

I think it should use the minimum of the values if max_height < 0. so.
int size = max_height < 0 ? max_width : (max_width < 0 ? max_height : MIN(max_height, max_width));

784 switch (category)
785 {
786 + case UNITY_PROTOCOL_CATEGORY_TYPE_BOOK:
787 + helper_handle =
788 + impl->LoadFromFilename(PKGDATADIR"/emblem_books.svg", -1, cat_size, helper_slot);
789 + break;
790 case UNITY_PROTOCOL_CATEGORY_TYPE_MUSIC:

Could we put the category->resource mapping in the Dash Style?

Other than these the code looks good. I trust it meets visual design requirements :)