Drop unused shader support for sample variables

Bug: skia:
Change-Id: I9e2b7da8c916703027d8dd4303ae67f4e69bcf87
Reviewed-on: https://skia-review.googlesource.com/107356
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/glsl/GrGLSLShaderBuilder.h b/src/gpu/glsl/GrGLSLShaderBuilder.h
index 0708625..8459218 100644
--- a/src/gpu/glsl/GrGLSLShaderBuilder.h
+++ b/src/gpu/glsl/GrGLSLShaderBuilder.h
@@ -173,9 +173,7 @@
         kTexelBuffer_GLSLPrivateFeature,
         kFramebufferFetch_GLSLPrivateFeature,
         kNoPerspectiveInterpolation_GLSLPrivateFeature,
-        kSampleVariables_GLSLPrivateFeature,
-        kSampleMaskOverrideCoverage_GLSLPrivateFeature,
-        kLastGLSLPrivateFeature = kSampleMaskOverrideCoverage_GLSLPrivateFeature
+        kLastGLSLPrivateFeature = kNoPerspectiveInterpolation_GLSLPrivateFeature
     };
 
     /*