Revert of Change SkShader;asFragmentProcessor signature to no longer take skpaint\grcolor*

src/gpu/effects/GrConvolutionEffect.cpp

Index: src/gpu/effects/GrConvolutionEffect.cpp
diff --git a/src/gpu/effects/GrConvolutionEffect.cpp b/src/gpu/effects/GrConvolutionEffect.cpp
index 5fd62b8cdfeed43f75604c31fae950b0d3c88e6c..f70b664505456107f28b85ab99e0d1c46abd76a4 100644
--- a/src/gpu/effects/GrConvolutionEffect.cpp
+++ b/src/gpu/effects/GrConvolutionEffect.cpp
@@ -217,7 +217,7 @@
 
 GR_DEFINE_FRAGMENT_PROCESSOR_TEST(GrConvolutionEffect);
 
-const GrFragmentProcessor* GrConvolutionEffect::TestCreate(GrProcessorTestData* d) {
+GrFragmentProcessor* GrConvolutionEffect::TestCreate(GrProcessorTestData* d) {
     int texIdx = d->fRandom->nextBool() ? GrProcessorUnitTest::kSkiaPMTextureIdx :
                                           GrProcessorUnitTest::kAlphaTextureIdx;
     Direction dir = d->fRandom->nextBool() ? kX_Direction : kY_Direction;