Code review comment for lp://qastaging/~nick-dedekind/unity/lp1066788.cairo-text-stitching

Hmm code looks good, and confirmed fixes the crash for me...but there is no test :(

Possibly add a manual test that says to open the StandaloneApplicationPreivew...(but they would have to compile...)

Or possibly a unit test that would attempt to make a texture that is to large and confirm that it is not returning NULL.