disable legacy shaders in flutter

All of Flutter's non-test drawing is done with Ganesh,
and the few shaders that are legacy-only are not used by Flutter.

This should cut a bunch of essentially-dead code from Flutter, though
some of the Flutter test images may change because those test images are
software rasterized.  Hopefully nothing should look terribly different.

Looks like this cuts ~27K from Flutter.

Change-Id: I4c8078db17fe9d24b15ed9d8c6adb528a382f02a
Reviewed-on: https://skia-review.googlesource.com/c/163165
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
1 file changed