Add a class representing texture swizzle.

src/effects/SkColorCubeFilter.cpp

Index: src/effects/SkColorCubeFilter.cpp
diff --git a/src/effects/SkColorCubeFilter.cpp b/src/effects/SkColorCubeFilter.cpp
index 7f1f59622e57e2184ef9e247bc9960da06708c62..5f1f10d53f020f5192ba5c84c4f1e7a9fa714b5e 100644
--- a/src/effects/SkColorCubeFilter.cpp
+++ b/src/effects/SkColorCubeFilter.cpp
@@ -212,7 +212,7 @@ private:
 ///////////////////////////////////////////////////////////////////////////////
 
 GrColorCubeEffect::GrColorCubeEffect(GrTexture* colorCube)
-    : fColorCubeAccess(colorCube, "bgra", GrTextureParams::kBilerp_FilterMode) {
+    : fColorCubeAccess(colorCube, GrTextureParams::kBilerp_FilterMode) {
     this->initClassID<GrColorCubeEffect>();
     this->addTextureAccess(&fColorCubeAccess);
 }
@@ -287,11 +287,11 @@ void GrColorCubeEffect::GLSLProcessor::emitCode(EmitArgs& args) {
     // Apply the cube.
     fragBuilder->codeAppendf("%s = vec4(mix(", args.fOutputColor);
     fragBuilder->appendTextureLookup(args.fSamplers[0], cCoords1);
-    fragBuilder->codeAppend(".rgb, ");
+    fragBuilder->codeAppend(".bgr, ");
     fragBuilder->appendTextureLookup(args.fSamplers[0], cCoords2);
 
     // Premultiply color by alpha. Note that the input alpha is not modified by this shader.
-    fragBuilder->codeAppendf(".rgb, fract(%s.b)) * vec3(%s), %s.a);\n",
+    fragBuilder->codeAppendf(".bgr, fract(%s.b)) * vec3(%s), %s.a);\n",
                              cubeIdx, nonZeroAlpha, args.fInputColor);
 }