Add subsetting to SkScanlineDecoder

src/codec/SkCodec_wbmp.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 "SkCodec.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
@@ skipping 52 matching lines @@
     if (size) {
         *size = SkISize::Make(SkToS32(width), SkToS32(height));
     }
     return true;
 }
 
 bool SkWbmpCodec::onRewind() {
     return read_header(this->stream(), nullptr);
 }
 
-SkSwizzler* SkWbmpCodec::initializeSwizzler(const SkImageInfo& info,
-        const SkPMColor* ctable, const Options& opts) {
+SkSwizzler* SkWbmpCodec::initializeSwizzler(const SkImageInfo& info, const SkPMColor* ctable,
+        const Options& opts) {
     // Create the swizzler based on the desired color type
     switch (info.colorType()) {
         case kIndex_8_SkColorType:
         case kN32_SkColorType:
         case kRGB_565_SkColorType:
         case kGray_8_SkColorType:
             break;
         default:
             return nullptr;
     }
-    return SkSwizzler::CreateSwizzler(SkSwizzler::kBit, ctable, info,
-                                      opts.fZeroInitialized);
+    return SkSwizzler::CreateSwizzler(SkSwizzler::kBit, ctable, info, opts);
 }
 
 bool SkWbmpCodec::readRow(uint8_t* row) {
     return this->stream()->read(row, fSrcRowBytes) == fSrcRowBytes;
 }
 
 SkWbmpCodec::SkWbmpCodec(const SkImageInfo& info, SkStream* stream)
     : INHERITED(info, stream)
     , fSrcRowBytes(get_src_row_bytes(this->getInfo().width()))
     , fColorTable(nullptr)
@@ skipping 84 matching lines @@
 
     // Fill in the color table
     setup_color_table(dstInfo.colorType(), inputColorTable, inputColorCount);
 
     // Copy the color table to a pointer that can be owned by the scanline decoder
     if (kIndex_8_SkColorType == dstInfo.colorType()) {
         fColorTable.reset(new SkColorTable(inputColorTable, 2));
     }
 
     // Initialize the swizzler
-    fSwizzler.reset(this->initializeSwizzler(dstInfo,
-            get_color_ptr(fColorTable.get()), options));
+    fSwizzler.reset(this->initializeSwizzler(dstInfo, get_color_ptr(fColorTable.get()), options));
     if (nullptr == fSwizzler.get()) {
         return kInvalidConversion;
     }
 
     fSrcBuffer.reset(fSrcRowBytes);
 
     return kSuccess;
 }