We should have a struct more like SkSamplingOptions to handle the combinatorial explosion of possible sampling configurations, all of which both Impeller and Skia are able to support just fine (except for cubic resampling in Impeller).

As part of FragmentProgram, we allow users to create arbitrary samplers -- translating to this enum would back us into a corner for supporting the full gamut of sampling configurations in the future.

The data in the SkSamplingOptions is:

    const int              maxAniso = 0;
    const bool             useCubic = false;
    const SkCubicResampler cubic    = {0, 0};
    const SkFilterMode     filter   = SkFilterMode::kNearest;
    const SkMipmapMode     mipmap   = SkMipmapMode::kNone;

The presets made available by DlSamplingOptions are:

enum class DlImageSampling {
  kNearestNeighbor,
  kLinear,
  kMipmapLinear,
  kCubic,
};

(This enum landed as part of flutter/engine#34024)