Remove Index_8 handling in cacherator heuristic code

Constructor changes the color type to N32 now, so this
code is never needed.

Bug: skia:
Change-Id: If464440fed799122fed810d870f5d6d9a932bf12
Reviewed-on: https://skia-review.googlesource.com/13000
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
1 file changed