Implement onSkipScanlines() for bmp and wbmp

src/codec/SkBmpMaskCodec.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 "SkBmpMaskCodec.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
 
 /*
  * Creates an instance of the decoder
  */
 SkBmpMaskCodec::SkBmpMaskCodec(const SkImageInfo& info, SkStream* stream,
                                uint16_t bitsPerPixel, SkMasks* masks,
                                SkCodec::SkScanlineOrder rowOrder)
     : INHERITED(info, stream, bitsPerPixel, rowOrder)
     , fMasks(masks)
     , fMaskSwizzler(nullptr)
-    , fSrcRowBytes(SkAlign4(compute_row_bytes(this->getInfo().width(), this->bitsPerPixel())))
-    , fSrcBuffer(new uint8_t [fSrcRowBytes])
+    , fSrcBuffer(new uint8_t [this->srcRowBytes()])
 {}
 
 /*
  * Initiates the bitmap decode
  */
 SkCodec::Result SkBmpMaskCodec::onGetPixels(const SkImageInfo& dstInfo,
                                             void* dst, size_t dstRowBytes,
                                             const Options& opts,
                                             SkPMColor* inputColorPtr,
                                             int* inputColorCount,
@@ skipping 52 matching lines @@
  * Performs the decoding
  */
 int SkBmpMaskCodec::decodeRows(const SkImageInfo& dstInfo,
                                            void* dst, size_t dstRowBytes,
                                            const Options& opts) {
     // Iterate over rows of the image
     uint8_t* srcRow = fSrcBuffer.get();
     const int height = dstInfo.height();
     for (int y = 0; y < height; y++) {
         // Read a row of the input
-        if (this->stream()->read(srcRow, fSrcRowBytes) != fSrcRowBytes) {
+        if (this->stream()->read(srcRow, this->srcRowBytes()) != this->srcRowBytes()) {
             SkCodecPrintf("Warning: incomplete input stream.\n");
             return y;
         }
 
         // Decode the row in destination format
         uint32_t row = this->getDstRow(y, height);
         void* dstRow = SkTAddOffset<void>(dst, row * dstRowBytes);
         fMaskSwizzler->swizzle(dstRow, srcRow);
     }
 
     // Finished decoding the entire image
     return height;
 }