[PATCH v2 0/5] MR3524: gdiplus: Add missing PNG metadata properties

[Jeffrey Smith (＠whydoubt)]

This adds the unit, date-time, and palette histogram metadata properties for PNG images to GDI+.  With these changes, the properties returned match Windows for all files in the PNG samples suite found at http://www.schaik.com/pngsuite/ .

--
  v2: gdiplus: Set PNG palette histogram property when present.
      gdiplus: Set PNG date-time property when present.
      gdiplus: Set PNG unit properties always.
      gdiplus: Refactor png_metadata_reader.
      gdiplus/tests: Factor out check_properties functions.
 
https://gitlab.winehq.org/wine/wine/-/merge_requests/3524