bug fix for cubic low precision

src/gpu/effects/GrBezierEffect.cpp

Index: src/gpu/effects/GrBezierEffect.cpp
diff --git a/src/gpu/effects/GrBezierEffect.cpp b/src/gpu/effects/GrBezierEffect.cpp
index f38a136992a14103f850b28e7b63b9fbf8168cb4..1b14d349dd9fc29688a0604650926466dc20def2 100644
--- a/src/gpu/effects/GrBezierEffect.cpp
+++ b/src/gpu/effects/GrBezierEffect.cpp
@@ -321,7 +321,7 @@ void GrGLCubicEffect::emitCode(const EmitArgs& args) {
     const GrCubicEffect& gp = args.fGP.cast<GrCubicEffect>();
 
     GrGLVertToFrag v(kVec4f_GrSLType);
-    args.fPB->addVarying("CubicCoeffs", &v);
+    args.fPB->addVarying("CubicCoeffs", &v, GrGLShaderVar::kHigh_Precision);
     vsBuilder->codeAppendf("%s = %s;", v.vsOut(), gp.inCubicCoeffs()->fName);
 
     // setup coord outputs