Reenable index8 dsts

This is causing problems with image-cacherator-from-ctable gm.

In that gm, we use an index8->index8 readPixels() to take
a subset.

I think we need to keep this as long as we support index8 in the
generator/cacherator.  Though it's really strange because
we don't really bother to verify that color tables are the same
and we don't try to overwrite the dst color table...

BUG=skia:

Change-Id: Icf008caa571c4b81a52a23b8b7d9226789626ef5
Reviewed-on: https://skia-review.googlesource.com/7424
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed