basePosition      139 Source/core/page/DOMSelection.cpp     return shadowAdjustedNode(basePosition(visibleSelection()));
basePosition      147 Source/core/page/DOMSelection.cpp     return shadowAdjustedOffset(basePosition(visibleSelection()));
basePosition     1310 Source/web/WebFrameImpl.cpp     VisiblePosition basePosition = visiblePositionForWindowPoint(base);
basePosition     1312 Source/web/WebFrameImpl.cpp     VisibleSelection newSelection = VisibleSelection(basePosition, extentPosition);