Split SkBmpCodec into three separate classes

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.
  */
+#ifndef SkMaskSwizzler_DEFINED
+#define SkMaskSwizzler_DEFINED
 
 #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,
                                               SkMasks* masks,
                                               uint32_t bitsPerPixel);
 
     /*
-     *
      * Swizzle a row
-     *
      */
     SkSwizzler::ResultAlpha swizzle(void* dst, const uint8_t* SK_RESTRICT src);
 
 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);
 
     // Fields
     const SkImageInfo& fDstInfo;
     SkMasks*           fMasks;       // unowned
     const RowProc      fRowProc;
 };
+
+#endif