Reland "Add idea of DataType to SkYUVAPixmapInfo."

This is a reland of ed6344458750c0389b7ccce588b96d0c25397b19

Original change's description:
> Add idea of DataType to SkYUVAPixmapInfo.
> 
> DataType describes the data type of YUVA channels
> independent of how they are grouped into planes.
> 
> Adds mapping functions between SkColorType/channel count
> and DataType.
> 
> SkYUVAPixmapInfo can be constructed from DataType and will
> choose appropriate SkColorTypes for each plane.
> 
> Valid SkYUVAPixmapInfos now have the same DataType for each
> plane (could relax this in the future, esp for alpha plane).
> 
> SkYUVAPixmapInfo::SupportedDataTypes specifies the supported
> combinations of SkYUVAInfo::PlanarConfig and
> kYUVAPixmapInfo::DataType supported by a GrContext (based on
> supported texture formats).
> 
> SkImageGenerator/SkCodec YUVA query API now takes a
> SupportedDataTypes.
> 
> Change-Id: I8791234638e6ba3396d1e7960b7bc210edc6dd57
> Bug: skia:10632
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/314276
> Reviewed-by: Leon Scroggins <scroggo@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Commit-Queue: Brian Salomon <bsalomon@google.com>

Bug: skia:10632
Change-Id: I35b55b7477c11c822fdb3729a9f84acff1eb785d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/315284
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
19 files changed