Revert of Add SkCodec, including PNG implementation.

src/codec/SkCodec.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 "SkCodec.h"
-#include "SkData.h"
-#include "SkCodec_libpng.h"
-#include "SkStream.h"
-
-SkCodec* SkCodec::NewFromStream(SkStream* stream) {
-    if (!stream) {
-        return NULL;
-    }
-    SkAutoTDelete<SkStream> streamDeleter(stream);
-    const bool isPng = SkPngCodec::IsPng(stream);
-    // TODO: Avoid rewinding.
-    if (!stream->rewind()) {
-        return NULL;
-    }
-    if (isPng) {
-        streamDeleter.detach();
-        return SkPngCodec::NewFromStream(stream);
-    }
-    // TODO: Check other image types.
-    return NULL;
-}
-
-SkCodec* SkCodec::NewFromData(SkData* data) {
-    if (!data) {
-        return NULL;
-    }
-    return NewFromStream(SkNEW_ARGS(SkMemoryStream, (data)));
-}
-
-SkCodec::SkCodec(const SkImageInfo& info, SkStream* stream)
-    : fInfo(info)
-    , fStream(stream)
-    , fNeedsRewind(false)
-{}
-
-bool SkCodec::rewindIfNeeded() {
-    // Store the value of fNeedsRewind so we can update it. Next read will
-    // require a rewind.
-    const bool neededRewind = fNeedsRewind;
-    fNeedsRewind = true;
-    return !neededRewind || fStream->rewind();
-}