computeSourceImageRectForDirtyRect  337 Source/core/rendering/FilterEffectRenderer.cpp     IntRect filterSourceRect = pixelSnappedIntRect(filter->computeSourceImageRectForDirtyRect(filterBoxRect, dirtyRect));
computeSourceImageRectForDirtyRect  104 Source/core/rendering/FilterEffectRenderer.h     LayoutRect computeSourceImageRectForDirtyRect(const LayoutRect& filterBoxRect, const LayoutRect& dirtyRect);