Option for SkCodec to treat dst as all zeroes.

src/codec/SkSwizzler.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 "SkColorPriv.h"
 #include "SkSwizzler.h"
 #include "SkTemplates.h"
@@ skipping 117 matching lines @@
         }
         src += deltaSrc;
         alphaMask &= alpha;
     }
     return alphaMask != 0xFF;
 }
 */
 
 SkSwizzler* SkSwizzler::CreateSwizzler(SkSwizzler::SrcConfig sc, const SkPMColor* ctable,
                                        const SkImageInfo& info, void* dst,
-                                       size_t dstRowBytes, bool skipZeroes) {
+                                       size_t dstRowBytes, SkCodec::ZeroInitialized zeroInit) {
     if (info.colorType() == kUnknown_SkColorType) {
         return NULL;
     }
     if (info.minRowBytes() > dstRowBytes) {
         return  NULL;
     }
     if (kIndex == sc && NULL == ctable) {
         return NULL;
     }
     RowProc proc = NULL;
     switch (sc) {
         case kIndex:
             switch (info.colorType()) {
                 case kN32_SkColorType:
                     // We assume the color premultiplied ctable (or not) as desired.
-                    if (skipZeroes) {
+                    if (SkCodec::kYes_ZeroInitialized == zeroInit) {
                         proc = &swizzle_index_to_n32_skipZ;
                     } else {
                         proc = &swizzle_index_to_n32;
                     }
                     break;
                     
                 default:
                     break;
             }
             break;
         case kRGBX:
             // TODO: Support other swizzles.
             switch (info.colorType()) {
                 case kN32_SkColorType:
                     proc = &swizzle_rgbx_to_n32;
                     break;
                 default:
                     break;
             }
             break;
         case kRGBA:
             switch (info.colorType()) {
                 case kN32_SkColorType:
                     if (info.alphaType() == kUnpremul_SkAlphaType) {
-                        // Respect skipZeroes?
+                        // Respect zeroInit?
                         proc = &swizzle_rgba_to_n32_unpremul;
                     } else {
-                        if (skipZeroes) {
+                        if (SkCodec::kYes_ZeroInitialized == zeroInit) {
                             proc = &swizzle_rgba_to_n32_premul_skipZ;
                         } else {
                             proc = &swizzle_rgba_to_n32_premul;
                         }
                     }
                     break;
                 default:
                     break;
             }
             break;
@@ skipping 19 matching lines @@
 }
 
 bool SkSwizzler::next(const uint8_t* SK_RESTRICT src) {
     SkASSERT(fCurrY < fDstInfo.height());
     const bool hadAlpha = fRowProc(fDstRow, src, fDstInfo.width(), fSrcPixelSize,
                                    fCurrY, fColorTable);
     fCurrY++;
     fDstRow = SkTAddOffset<void>(fDstRow, fDstRowBytes);
     return hadAlpha;
 }