Add TraceHook support to skvm interpreter.

This provides a callback mechanism for the interpreter when a trace
opcode is encountered. The callbacks are only invoked when the trace
mask is enabled.

Change-Id: I55db22e18106ae09e4ab0a503533d830282c772c
Bug: skia:12614
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/473139
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
5 files changed