Deserialize pictures with custom image-deserializer

include/core/SkImageDeserializer.h

+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkImageDeserializer_DEFINED
+#define SkImageDeserializer_DEFINED
+
+#include "SkRefCnt.h"
+
+struct SkIRect;
+class SkData;
+class SkImage;
+
+class SK_API SkImageDeserializer {
+public:
+    virtual ~SkImageDeserializer() {}
+
+    /**
+     *  Given a data containing serialized content, return an SkImage from it.
+     *
+     *  @param data The data containing the encoded image. The subclass may ref this for later
+     *              decoding, or read it and process it immediately.
+     *  @param subset Optional rectangle represent the subset of the encoded data that is being
+     *                requested to be turned into an image.
+     *  @return The new image, or nullptr on failure.
+     *
+     *  The default implementation is to call SkImage::MakeFromEncoded(...)
+     */
+    virtual sk_sp<SkImage> makeFromData(SkData*, const SkIRect* subset);
+    virtual sk_sp<SkImage> makeFromMemory(const void* data, size_t length, const SkIRect* subset);
+};
+
+#endif