isFirstRegion     366 Source/core/rendering/RenderMultiColumnSet.cpp     LayoutRect overflowRect = overflowRectForFlowThreadPortion(portionRect, isFirstColumn && isFirstRegion(), isLastColumn && isLastRegion());
isFirstRegion      71 Source/core/rendering/RenderRegion.cpp     return overflowRectForFlowThreadPortion(flowThreadPortionRect(), isFirstRegion(), isLastRegion());
isFirstRegion      62 Source/core/rendering/RenderRegion.h     bool isFirstRegion() const;