Refactor how we store and use samplers in Ganesh

src/gpu/effects/GrTextureDomain.cpp

Index: src/gpu/effects/GrTextureDomain.cpp
diff --git a/src/gpu/effects/GrTextureDomain.cpp b/src/gpu/effects/GrTextureDomain.cpp
index 4394c0ed64d608a6abeb4e09a080eead1141dc06..9c648710d90add83ff14674c8ddfe7899ccf6890 100644
--- a/src/gpu/effects/GrTextureDomain.cpp
+++ b/src/gpu/effects/GrTextureDomain.cpp
@@ -192,13 +192,14 @@ void GrGLTextureDomainEffect::emitCode(EmitArgs& args) {
 
     GrGLSLFPFragmentBuilder* fragBuilder = args.fFragBuilder;
     SkString coords2D = fragBuilder->ensureFSCoords2D(args.fCoords, 0);
+    const GrGLSLSampler& sampler = args.fUniformHandler->getSampler(args.fTexSamplers[0]);
     fGLDomain.sampleTexture(fragBuilder,
                             args.fUniformHandler,
                             args.fGLSLCaps,
                             domain,
                             args.fOutputColor,
                             coords2D,
-                            args.fTexSamplers[0],
+                            sampler,
                             args.fInputColor);
 }