change pixel-serializer to support reencoding existing data

src/images/SkImageEncoder.cpp

 /*
  * Copyright 2009 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkImageEncoder.h"
 #include "SkBitmap.h"
 #include "SkStream.h"
@@ skipping 42 matching lines @@
 
 SkData* SkImageEncoder::EncodeData(const SkImageInfo& info, const void* pixels, size_t rowBytes,
                                    Type t, int quality) {
     SkBitmap bm;
     if (!bm.installPixels(info, const_cast<void*>(pixels), rowBytes)) {
         return nullptr;
     }
     SkAutoTDelete<SkImageEncoder> enc(SkImageEncoder::Create(t));
     return enc.get() ? enc.get()->encodeData(bm, quality) : nullptr;
 }
+
+SkData* SkImageEncoder::EncodeData(const SkPixmap& pmap, Type t, int quality) {
+    return EncodeData(pmap.info(), pmap.addr(), pmap.rowBytes(), t, quality);
+}
+
+SkData* SkImageEncoder::ReencodeData(SkData* encoded, Type t) {
+    SkAutoTDelete<SkImageEncoder> enc(SkImageEncoder::Create(t));
+    return enc.get() ? enc.get()->onReencodeData(encoded) : nullptr;
+}
+