added support for glMinSampleShading
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1812223002

Review URL: https://codereview.chromium.org/1812223002
diff --git a/include/gpu/gl/GrGLFunctions.h b/include/gpu/gl/GrGLFunctions.h
index 5708cce..ea1ed65 100644
--- a/include/gpu/gl/GrGLFunctions.h
+++ b/include/gpu/gl/GrGLFunctions.h
@@ -235,6 +235,9 @@
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLProgramUniformHandleui64Proc)(GrGLuint program, GrGLint location, GrGLuint64 v0);
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLProgramUniformHandleui64vProc)(GrGLuint program, GrGLint location, GrGLsizei count, const GrGLuint64 *value);
 
+/* ARB_sample_shading */
+typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLMinSampleShadingProc)(GrGLfloat value);
+
 /* EXT_direct_state_access */
 // (In the future some of these methods may be omitted)
 typedef GrGLvoid (GR_GL_FUNCTION_TYPE* GrGLTextureParameteriProc)(GrGLuint texture, GrGLenum target, GrGLenum pname, GrGLint param);