Fix SkSwizzler bug

src/codec/SkMaskSwizzler.h

Index: src/codec/SkMaskSwizzler.h
diff --git a/src/codec/SkMaskSwizzler.h b/src/codec/SkMaskSwizzler.h
index 0513d838c743975759d51c1fd05164f21593b5ab..25af41037b0f60012cacfa07015f9811c1459a0f 100644
--- a/src/codec/SkMaskSwizzler.h
+++ b/src/codec/SkMaskSwizzler.h
@@ -64,7 +64,7 @@ private:
     const RowProc   fRowProc;
 
     // FIXME: Can this class share more with SkSwizzler? These variables are all the same.
-    const int       fSrcWidth;        // Width of the source - i.e. before any sampling.
+    const int       fSubsetWidth;     // Width of the subset of source before any sampling.
     int             fDstWidth;        // Width of dst, which may differ with sampling.
     int             fSampleX;
     int             fX0;