Remove SK_SUPPORT_LEGACY_GRADIENT_COLOR_CONVERSION

The original change didn't produce any diffs, so this flag is not
useful.

TBR=

Change-Id: Ic4c8d6dcd7d03ace8624345fd624bc5840b99d27
Reviewed-on: https://skia-review.googlesource.com/67724
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed