Brought calculation into a central place so the loop did not have to
recalculate everything before the previous entry to find the inverse
index. O(n) vs O(n^2). Assumes an increasing (or at least
non-decreasing) table gamma just as the previous code did.
BUG=skia:
Change-Id: I7ea200c06511b3d74745fe4a6e3dde706bbee02f
Reviewed-on: https://skia-review.googlesource.com/5402
Commit-Queue: Robert Aftias <raftias@google.com>
Reviewed-by: Matt Sarett <msarett@google.com>
197e311ac9