how SkFontMgr to release font from font file

[Elliot Liu]

recently, I tried to use SkParagraph to render text.

And create new FontProvider, and register the font from font file.

But be noted the font data will not be released even I exit the function call.

Any idea will be appreciated. 

Code mostly like below:

sk_sp<SkData> fontData = SkData::MakeFromFileName(m_fontFile.c_str());

    sk_sp<TypefaceFontProvider> fontProvider = sk_make_sp<TypefaceFontProvider>();

    auto newFont = SkTypeface::MakeFromData(fontData);

    if (fontProvider->registerTypeface(newFont, m_fontName) == 0)