Don't allow negative width for positioned elements

Source/core/rendering/RenderBox.cpp

Index: Source/core/rendering/RenderBox.cpp
diff --git a/Source/core/rendering/RenderBox.cpp b/Source/core/rendering/RenderBox.cpp
index ef86f2943fdc59b3cad488d411f7f2720369d011..7f49a876f9273f1109db01f3d90f58634cdd9ca4 100644
--- a/Source/core/rendering/RenderBox.cpp
+++ b/Source/core/rendering/RenderBox.cpp
@@ -3295,7 +3295,7 @@ void RenderBox::computePositionedLogicalWidthUsing(Length logicalWidth, const Re
             if (autoWidthShouldFitContent())
                 shrinkToFitWidth(availableSpace, logicalLeftValue, bordersPlusPadding, computedValues);
             else
-                computedValues.m_extent = availableSpace - (logicalLeftValue + valueForLength(logicalRight, containerLogicalWidth));
+                computedValues.m_extent = std::max<LayoutUnit>(0, availableSpace - (logicalLeftValue + valueForLength(logicalRight, containerLogicalWidth)));
         } else if (!logicalLeftIsAuto && !logicalWidthIsAuto && logicalRightIsAuto) {
             // RULE 6: (no need solve for right)
             logicalLeftValue = valueForLength(logicalLeft, containerLogicalWidth);