Add private GrContext::compile API (take 2)

Currently this is only implemented for GL.

Bug: skia:9455
Change-Id: I851471d6334d6a38e6fde3a46f09b7dc0209fb78
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/272346
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/vk/GrVkGpu.h b/src/gpu/vk/GrVkGpu.h
index 1156d90..fe6375e 100644
--- a/src/gpu/vk/GrVkGpu.h
+++ b/src/gpu/vk/GrVkGpu.h
@@ -75,6 +75,9 @@
     void xferBarrier(GrRenderTarget*, GrXferBarrierType) override {}
 
     void deleteBackendTexture(const GrBackendTexture&) override;
+
+    bool compile(const GrProgramDesc&, const GrProgramInfo&) override;
+
 #if GR_TEST_UTILS
     bool isTestingOnlyBackendTexture(const GrBackendTexture&) const override;