fLuminance is unsed unless SK_GAMMA_APPLY_TO_A8 is defined

src/gpu/effects/GrDistanceFieldTextureEffect.cpp

Index: src/gpu/effects/GrDistanceFieldTextureEffect.cpp
diff --git a/src/gpu/effects/GrDistanceFieldTextureEffect.cpp b/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
index f65492e9f08d31493d98537d47178664b3365b4a..28220a72ec72dcf2b7489e79587de8d961a1c1f9 100755
--- a/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
+++ b/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
@@ -185,7 +185,9 @@ private:
     UniformHandle fTextureSizeUni;
     SkISize       fTextureSize;
     UniformHandle fLuminanceUni;
+#ifdef SK_GAMMA_APPLY_TO_A8
     float         fLuminance;
+#endif
 
     typedef GrGLGeometryProcessor INHERITED;
 };