it is inefficient to allocate a tiny object like Color separately on the
heap

Change-Id: Iac2cfc7c00c16240e7cf72e7d8814e97e9f65ac6
Reviewed-on: https://gerrit.libreoffice.org/67967
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>