Support RGBA/BGRA swizzles using SkEncodedInfo

src/codec/SkGifCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
 #include "SkColorTable.h"
@@ skipping 392 matching lines @@
     if (NULL == colorMap) {
         colorMap = fGif->SColorMap;
     }
 
     uint32_t colorCount = 0;
     if (NULL != colorMap) {
         colorCount = colorMap->ColorCount;
         // giflib guarantees these properties
         SkASSERT(colorCount == (unsigned) (1 << (colorMap->BitsPerPixel)));
         SkASSERT(colorCount <= 256);
+        PackColorProc proc = choose_pack_color_proc(false, dstInfo.colorType());
         for (uint32_t i = 0; i < colorCount; i++) {
-            colorPtr[i] = SkPackARGB32(0xFF, colorMap->Colors[i].Red,
+            colorPtr[i] = proc(0xFF, colorMap->Colors[i].Red,
                     colorMap->Colors[i].Green, colorMap->Colors[i].Blue);
         }
     }
 
     // Fill in the color table for indices greater than color count.
     // This allows for predictable, safe behavior.
     if (colorCount > 0) {
         // Gifs have the option to specify the color at a single index of the color
         // table as transparent.  If the transparent index is greater than the
         // colorCount, we know that there is no valid transparent color in the color
@@ skipping 32 matching lines @@
     // Initialize color table and copy to the client if necessary
     this->initializeColorTable(dstInfo, inputColorPtr, inputColorCount);
 
     this->initializeSwizzler(dstInfo, opts);
     return kSuccess;
 }
 
 void SkGifCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& opts) {
     const SkPMColor* colorPtr = get_color_ptr(fColorTable.get());
     const SkIRect* frameRect = fFrameIsSubset ? &fFrameRect : nullptr;
-    fSwizzler.reset(SkSwizzler::CreateSwizzler(SkSwizzler::kIndex, colorPtr, dstInfo, opts,
+    fSwizzler.reset(SkSwizzler::CreateSwizzler(this->getEncodedInfo(), colorPtr, dstInfo, opts,
             frameRect));
     SkASSERT(fSwizzler);
 }
 
 bool SkGifCodec::readRow() {
     return GIF_ERROR != DGifGetLine(fGif, fSrcBuffer.get(), fFrameRect.width());
 }
 
 /*
  * Initiates the gif decode
@@ skipping 119 matching lines @@
 int SkGifCodec::onOutputScanline(int inputScanline) const {
     if (fGif->Image.Interlace) {
         if (inputScanline < fFrameRect.top() || inputScanline >= fFrameRect.bottom()) {
             return inputScanline;
         }
         return get_output_row_interlaced(inputScanline - fFrameRect.top(), fFrameRect.height()) +
                 fFrameRect.top();
     }
     return inputScanline;
 }