Clean up unused or overly complex modes in SkSwizzler

src/codec/SkJpegCodec.cpp

Index: src/codec/SkJpegCodec.cpp
diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index 7db772da6386ad9a3b0002d5334598a625fd6fa2..89925fb4645979e78721e0ad75a162cb59f72c3d 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -329,18 +329,17 @@ void SkJpegCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options&
     if (JCS_CMYK == fDecoderMgr->dinfo()->out_color_space) {
         srcConfig = SkSwizzler::kCMYK;
     } else {
+        // If the out_color_space is not CMYK, the only reason we would need a swizzler is
+        // for sampling and/or subsetting.
         switch (dstInfo.colorType()) {
             case kGray_8_SkColorType:
-                srcConfig = SkSwizzler::kGray;
+                srcConfig = SkSwizzler::kNoOp8;
                 break;
-            case kRGBA_8888_SkColorType:
-                srcConfig = SkSwizzler::kRGBX;
-                break;
-            case kBGRA_8888_SkColorType:
-                srcConfig = SkSwizzler::kBGRX;
+            case kN32_SkColorType:
+                srcConfig = SkSwizzler::kNoOp32;
                 break;
             case kRGB_565_SkColorType:
-                srcConfig = SkSwizzler::kRGB_565;
+                srcConfig = SkSwizzler::kNoOp16;
                 break;
             default:
                 // This function should only be called if the colorType is supported by jpeg