Make texture created by SkColorSpaceXformImageGenerator be the right size

Previously it was the size of the original image with the subset contents at the top left.

Change-Id: I9a50e44e5666acb06d9c3cfbb850c31e52a9e405
Reviewed-on: https://skia-review.googlesource.com/36441
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
1 file changed