add vtune support back

I spent a little time working on adding the --dylib JIT
mode to Windows where we'd shell out to Clang to make a .dll,
but then I remembered this VTune JIT API.

That dylib approach is nice for working with a wide range
of tools (perf, Instruments, gdb, etc.), but when your only
need is Vtune, this API is actually the best option.  You
get your profiler aware of your JIT'd code with way less
overhead than the shell-then-dlopen approach.

If we need to expand to more tools I'll go make the dylib
mode work, but I think this is good enough to make me happy
on Windows for now.

This should look really similar to
https://skia-review.googlesource.com/c/skia/+/255124.

Change-Id: I9e283cdf9bdfeb11c647a2315a7916dc68ef73c7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/301935
Commit-Queue: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Herb Derby <herb@google.com>
diff --git a/BUILD.gn b/BUILD.gn
index af9134b..4297a83 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -954,6 +954,11 @@
 optional("skvm_jit") {
   enabled = skia_enable_skvm_jit
   public_defines = [ "SKVM_JIT" ]
+  if (skia_vtune_path != "") {
+    public_defines += [ "SKVM_JIT_VTUNE" ]
+    public_include_dirs = [ "$skia_vtune_path/include" ]
+    libs = [ "$skia_vtune_path/lib64/jitprofiling.lib" ]
+  }
 }
 
 if (skia_enable_gpu && skia_generate_workarounds) {