HRESULT SkScalerContext_DW::getBoundingBox(SkGlyph* glyph,
        DWRITE_RENDERING_MODE renderingMode,
        DWRITE_TEXTURE_TYPE textureType,
        RECT* bbox)
{
    //Measure raster size.
    fXform.dx = SkFixedToFloat(glyph->getSubXFixed());
    fXform.dy = SkFixedToFloat(glyph->getSubYFixed());

    FLOAT advance = 0;

    UINT16 glyphId = glyph->getGlyphID();

    DWRITE_GLYPH_OFFSET offset;
    offset.advanceOffset = 0.0f;
    offset.ascenderOffset = 0.0f;

    DWRITE_GLYPH_RUN run;
    run.glyphCount = 1;
    run.glyphAdvances = &advance;
    run.fontFace = fTypeface->fDWriteFontFace.get();
    run.fontEmSize = SkScalarToFloat(fTextSizeRender);
    run.bidiLevel = 0;
    run.glyphIndices = &glyphId;
    run.isSideways = FALSE;
    run.glyphOffsets = &offset;

    SkTScopedComPtr<IDWriteGlyphRunAnalysis> glyphRunAnalysis;
    {
        SkAutoExclusive l(DWriteFactoryMutex);
        HRM(fTypeface->fFactory->CreateGlyphRunAnalysis(
                &run,
                1.0f, // pixelsPerDip,
                &fXform,
                renderingMode,
                fMeasuringMode,
                0.0f, // baselineOriginX,
                0.0f, // baselineOriginY,
                &glyphRunAnalysis),
            "Could not create glyph run analysis.");
    }
    {
        Shared l(DWriteFactoryMutex);
        HRM(glyphRunAnalysis->GetAlphaTextureBounds(textureType, bbox),
            "Could not get texture bounds.");
    }
    return S_OK;
}