Hook up persistent shader cache for D3D

Currently supports SkSL & HLSL. We should see if we can safely serialize
the shader blobs returned by D3DCompile.

We can't (yet) view the HLSL in Viewer - the shader viewer/editor needs
an overhaul to support backend-specific source formats (MSL, HLSL,
disassembled SPIRV). Going to look into that in a separate CL.

Change-Id: Ife1fd1d3d724674b24793df2d86c52a9b8f7de23
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/296734
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
5 files changed