Make SkGIFLZWBlock modifiable so it is assignable

std::vector needs to be able to assign objects contained inside it. With
const member variables, this isn't possible. Remove the consts so
SkGIFLZWBlock can be assigned.

BUG=skia:6072

Change-Id: I990dc80fb1c49fbd584712c6d0c1154c2da36e85
Reviewed-on: https://skia-review.googlesource.com/6362
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
1 file changed