Split SkBmpCodec into three separate classes

src/codec/SkMaskSwizzler.h

Index: src/codec/SkMaskSwizzler.h
diff --git a/src/codec/SkMaskSwizzler.h b/src/codec/SkMaskSwizzler.h
index 4ccc3ae4a427a1275401c859b53f4570f975be1c..9f4dd440aa27e5b5961065f28cd5f0348d6a0524 100644
--- a/src/codec/SkMaskSwizzler.h
+++ b/src/codec/SkMaskSwizzler.h
@@ -4,6 +4,8 @@
  * 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"
@@ -19,37 +21,29 @@ 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);
 
@@ -58,3 +52,5 @@ private:
     SkMasks*           fMasks;       // unowned
     const RowProc      fRowProc;
 };
+
+#endif