SkSwizzler: Factor skipping zeros out into a helper function.

src/codec/SkSwizzler.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkSwizzler_DEFINED
 #define SkSwizzler_DEFINED
 
@@ skipping 174 matching lines @@
      *  @param deltaSrc bpp * sampleX
      *  @param ctable Colors (used for kIndex source).
      *  @param offset The offset before the first pixel to sample.
                         Is in bytes or bits based on what deltaSrc is in.
      */
     typedef ResultAlpha (*RowProc)(void* SK_RESTRICT dstRow,
                                    const uint8_t* SK_RESTRICT src,
                                    int dstWidth, int bpp, int deltaSrc, int offset,
                                    const SkPMColor ctable[]);
 
+    template <RowProc proc>
+    static ResultAlpha SkipLeading8888ZerosThen(void* SK_RESTRICT dstRow,
+                                                const uint8_t* SK_RESTRICT src,
+                                                int dstWidth, int bpp, int deltaSrc, int offset,
+                                                const SkPMColor ctable[]);
+
     const RowProc       fRowProc;
     const SkPMColor*    fColorTable;      // Unowned pointer
 
     // Subset Swizzles
     // There are two types of subset swizzles that we support.  We do not
     // support both at the same time.
     // TODO: If we want to support partial scanlines for gifs (which may
     //       use frame subsets), we will need to support both subsetting
     //       modes at the same time.
     // (1) Partial Scanlines
@@ skipping 74 matching lines @@
                                           //     fBPP is bitsPerPixel
     const int           fDstBPP;          // Bytes per pixel for the destination color type
 
     SkSwizzler(RowProc proc, const SkPMColor* ctable, int srcOffset, int srcWidth, int dstOffset,
             int dstWidth, int srcBPP, int dstBPP);
 
     int onSetSampleX(int) override;
 
 };
 #endif // SkSwizzler_DEFINED