Adding 3D lut color filter

src/gpu/gl/builders/GrGLProgramBuilder.cpp

Index: src/gpu/gl/builders/GrGLProgramBuilder.cpp
diff --git a/src/gpu/gl/builders/GrGLProgramBuilder.cpp b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
index a0dd555587f7a466f98bbfa48769443c1e6b8843..55ebf6890feac394f5bff386ca0a3f103ca67f55 100644
--- a/src/gpu/gl/builders/GrGLProgramBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
@@ -217,11 +217,14 @@ void GrGLProgramBuilder::emitSamplers(const GrEffect& effect,
     SkString name;
     for (int t = 0; t < numTextures; ++t) {
         name.printf("Sampler%d", t);
+        const GrTextureAccess& ta = effect.textureAccess(t);
+        const GrTexture* tex = ta.getTexture();
+        bool is3D = (tex != NULL) && (tex->desc().fDepth > 0);
         samplers[t].fUniform = this->addUniform(GrGLProgramBuilder::kFragment_Visibility,
-                                                kSampler2D_GrSLType,
+                                                is3D ? kSampler3D_GrSLType : kSampler2D_GrSLType,
                                                 name.c_str());
         SkNEW_APPEND_TO_TARRAY(outSamplers, GrGLEffect::TextureSampler,
-                               (samplers[t].fUniform, effect.textureAccess(t)));
+                               (samplers[t].fUniform, ta));
     }
 }