Add SkVMDebugInfo::setSource.

This associates the input SkSL source with our debug info. It is
serialized out to .trace files. This will actually let us display the
code associated with `trace_line`.

Bug: skia:12614
Change-Id: I6c10af6fa6dd97ed8411f3460e103f442722b7f6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/472999
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
4 files changed