Adding premul and 565 swizzles for bmp:

src/codec/SkMaskSwizzler.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.
  */
 
 #include "SkMasks.h"
 #include "SkSwizzler.h"
 #include "SkTypes.h"
 
 /*
  *
  * Used to swizzle images whose pixel components are extracted by bit masks
  * Currently only used by bmp
  *
  */
 class SkMaskSwizzler {
 public:
 
     /*
      *
      * Create a new swizzler
      * @param masks Unowned pointer to helper class
      *
      */
     static SkMaskSwizzler* CreateMaskSwizzler(const SkImageInfo& imageInfo,
+                                              void* dst, size_t dstRowBytes,
                                               SkMasks* masks,
                                               uint32_t bitsPerPixel);
 
     /*
      *
-     * Swizzle the next row
+     * Swizzle the row with the specified y value
      *
      */
-    SkSwizzler::ResultAlpha next(void* dst, const uint8_t* src);
+    SkSwizzler::ResultAlpha next(const uint8_t* SK_RESTRICT src, int y);
 
 private:
 
     /*
      *
      * Row procedure used for swizzle
      *
      */
     typedef SkSwizzler::ResultAlpha (*RowProc)(
             void* dstRow, const uint8_t* srcRow, int width,
             SkMasks* masks);
 
     /*
      *
      * Constructor for mask swizzler
      *
      */
-    SkMaskSwizzler(const SkImageInfo& info, SkMasks* masks, RowProc proc);
+    SkMaskSwizzler(const SkImageInfo& info, void* dst, size_t dstRowBytes,
+            SkMasks* masks, RowProc proc);
 
     // Fields
-    const SkImageInfo& fImageInfo;
-    SkMasks*           fMasks;     // unowned
+    const SkImageInfo& fDstInfo;
+    void*              fDst;
+    size_t             fDstRowBytes;
+    SkMasks*           fMasks;       // unowned
     const RowProc      fRowProc;
 };