Use SkOpts routines in SkSwizzler

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 142 matching lines @@
                             const uint8_t* SK_RESTRICT src,
                             int dstWidth, int bpp, int deltaSrc, int offset,
                             const SkPMColor ctable[]);
 
     template <RowProc Proc>
     static void 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;
+    // May be NULL.  We will not always be able to used an optimized function.
+    RowProc             fFastProc;
+    // Always non-NULL.  We use this if fFastProc is NULL.
+    const RowProc       fProc;
     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
     //         The client only wants to write a subset of the source pixels
@@ skipping 66 matching lines @@
     int                 fAllocatedWidth;
 
     int                 fSampleX;         // Step between X samples
     const int           fSrcBPP;          // Bits/bytes per pixel for the SrcConfig
                                           // if bitsPerPixel % 8 == 0
                                           //     fBPP is bytesPerPixel
                                           // else
                                           //     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);
+    SkSwizzler(RowProc fastProc, RowProc proc, const SkPMColor* ctable, int srcOffset,
+            int srcWidth, int dstOffset, int dstWidth, int srcBPP, int dstBPP);
 
     int onSetSampleX(int) override;
 
 };
 #endif // SkSwizzler_DEFINED