Decouple HLSL code generation from SkSL::Compiler.

Bug: b/317363889
Bug: b/40045064
Change-Id: Ic9b4b9920698207564291f26983fe159418156ca
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/793656
Reviewed-by: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
7 files changed