Revert of change pixel-serializer to support reencoding existing data

src/core/SkPixelSerializer.cpp

-/*
- * Copyright 2015 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "SkPixelSerializer.h"
-
-SkData* SkPixelSerializer::reencodeData(SkData* encoded) {
-    return encoded ? this->onReencodeData(encoded) : nullptr;
-}
-
-SkData* SkPixelSerializer::encodePixels(const SkImageInfo& info, const void* pixels,
-                                        size_t rowBytes) {
-    if (kUnknown_SkColorType == info.colorType() || !pixels) {
-        return nullptr;
-    }
-    return this->onEncodePixels(info, pixels, rowBytes);
-}
-
-SkData* SkPixelSerializer::encodePixels(const SkPixmap& pixmap) {
-    return this->encodePixels(pixmap.info(), pixmap.addr(), pixmap.rowBytes());
-}