Revert of change pixel-serializer to support reencoding existing data

tools/sk_tool_utils.h

Index: tools/sk_tool_utils.h
diff --git a/tools/sk_tool_utils.h b/tools/sk_tool_utils.h
index d8709cc71e721dbcbbb0ea8207d876508a36c5af..b20c60ba7632d9ed98f6f6cdd84f47e06ac4c99f 100644
--- a/tools/sk_tool_utils.h
+++ b/tools/sk_tool_utils.h
@@ -115,6 +115,7 @@
     // used.
     class PngPixelSerializer : public SkPixelSerializer {
     public:
+        bool onUseEncodedData(const void*, size_t) override { return true; }
         SkData* onEncodePixels(const SkImageInfo& info, const void* pixels,
                                size_t rowBytes) override {
             return SkImageEncoder::EncodeData(info, pixels, rowBytes,