In GLES always use HALF_FLOAT_OES with LUMINANCE.
In GLES always use HALF_FLOAT_OES with LUMINANCE.

In GLES 3.0+ even though HALF_FLOAT is a valid type it is not listed as
a valid type combination with LUMINANCE. Thus we need to still use the
type from the extension HALF_FLOAT_OES in combination with LUMINANCE.

Bug: b/238170249
Change-Id: I2adba67fa98a8adac0345f0af9783e299674f9c0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/557580
Reviewed-by: Jim Van Verth <509afb0bfbb23ecaaf1fb3323209f531b45e75a6@google.com>
Commit-Queue: Greg Daniel <39df0a804564ccb6cf75f18db79653821f37c1c5@google.com>

google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia