Adding 3D lut color filter

src/gpu/gl/GrGLProgramEffects.cpp

Index: src/gpu/gl/GrGLProgramEffects.cpp
diff --git a/src/gpu/gl/GrGLProgramEffects.cpp b/src/gpu/gl/GrGLProgramEffects.cpp
index 369ec1076030f25e8abccf694006692abb1fbf3a..222fa3c3d12db91d5bd43474d3b3cd7f83852b10 100644
--- a/src/gpu/gl/GrGLProgramEffects.cpp
+++ b/src/gpu/gl/GrGLProgramEffects.cpp
@@ -215,11 +215,12 @@ void GrGLProgramEffects::emitSamplers(GrGLProgramBuilder* builder,
     SkString name;
     for (int t = 0; t < numTextures; ++t) {
         name.printf("Sampler%d", t);
+        const GrTextureAccess& textureAccess = effect->textureAccess(t);
         samplers[t].fUniform = builder->addUniform(GrGLProgramBuilder::kFragment_Visibility,
-                                                   kSampler2D_GrSLType,
-                                                   name.c_str());
+            SkToBool(textureAccess.getTexture()->desc().fFlags & k3DTexture_GrTextureFlagBit) ?
+            kSampler3D_GrSLType : kSampler2D_GrSLType, name.c_str());
         SkNEW_APPEND_TO_TARRAY(outSamplers, TextureSampler,
-                               (samplers[t].fUniform, effect->textureAccess(t)));
+                               (samplers[t].fUniform, textureAccess));
     }
 }