Refactor how we store and use samplers in Ganesh

src/effects/SkColorCubeFilter.cpp

Index: src/effects/SkColorCubeFilter.cpp
diff --git a/src/effects/SkColorCubeFilter.cpp b/src/effects/SkColorCubeFilter.cpp
index d9e51127a4df8b530f537e872f674e2c21b73124..17e030da76793844567c6d9ad143be5e89372200 100644
--- a/src/effects/SkColorCubeFilter.cpp
+++ b/src/effects/SkColorCubeFilter.cpp
@@ -275,11 +275,12 @@ void GrColorCubeEffect::GLSLProcessor::emitCode(EmitArgs& args) {
     fragBuilder->codeAppendf("vec2 %s = vec2(%s.r, (ceil(%s.b) + %s.g) * %s);\n",
                              cCoords2, cubeIdx, cubeIdx, cubeIdx, colorCubeInvSizeUni);
 
+    const GrGLSLSampler& sampler = uniformHandler->getSampler(args.fTexSamplers[0]);
     // Apply the cube.
     fragBuilder->codeAppendf("%s = vec4(mix(", args.fOutputColor);
-    fragBuilder->appendTextureLookup(args.fTexSamplers[0], cCoords1);
+    fragBuilder->appendTextureLookup(sampler, cCoords1);
     fragBuilder->codeAppend(".bgr, ");
-    fragBuilder->appendTextureLookup(args.fTexSamplers[0], cCoords2);
+    fragBuilder->appendTextureLookup(sampler, cCoords2);
 
     // Premultiply color by alpha. Note that the input alpha is not modified by this shader.
     fragBuilder->codeAppendf(".bgr, fract(%s.b)) * vec3(%s), %s.a);\n",