Revert of Add SkPngChunkReader.

include/codec/SkCodec.h

Index: include/codec/SkCodec.h
diff --git a/include/codec/SkCodec.h b/include/codec/SkCodec.h
index dffab6b3779207aeba99084810afb27d8416a097..d90fea8cedcf6d92ecdc8535e71962faaa376689 100644
--- a/include/codec/SkCodec.h
+++ b/include/codec/SkCodec.h
@@ -17,7 +17,6 @@
 #include "SkTypes.h"
 
 class SkData;
-class SkPngChunkReader;
 class SkSampler;
 
 /**
@@ -29,24 +28,18 @@
      *  If this stream represents an encoded image that we know how to decode,
      *  return an SkCodec that can decode it. Otherwise return NULL.
      *
-     *  If SkPngChunkReader is not NULL, take a ref and pass it to libpng if
-     *  the image is a png.
-     *
      *  If NULL is returned, the stream is deleted immediately. Otherwise, the
      *  SkCodec takes ownership of it, and will delete it when done with it.
      */
-    static SkCodec* NewFromStream(SkStream*, SkPngChunkReader* = NULL);
+    static SkCodec* NewFromStream(SkStream*);
 
     /**
      *  If this data represents an encoded image that we know how to decode,
      *  return an SkCodec that can decode it. Otherwise return NULL.
      *
-     *  If SkPngChunkReader is not NULL, take a ref and pass it to libpng if
-     *  the image is a png.
-     *
      *  Will take a ref if it returns a codec, else will not affect the data.
      */
-    static SkCodec* NewFromData(SkData*, SkPngChunkReader* = NULL);
+    static SkCodec* NewFromData(SkData*);
 
     virtual ~SkCodec();