Prevent overflow of width/height of layout overflow rectangle which can cause scroll bar to misfunc…

Source/core/rendering/RenderOverflow.h

Index: Source/core/rendering/RenderOverflow.h
diff --git a/Source/core/rendering/RenderOverflow.h b/Source/core/rendering/RenderOverflow.h
index d01d3bae59190896538aa3546b2442e393dd8fde..81d7f40f2d96e96e7628038dc07fade28aef5366 100644
--- a/Source/core/rendering/RenderOverflow.h
+++ b/Source/core/rendering/RenderOverflow.h
@@ -87,10 +87,13 @@ inline void RenderOverflow::addLayoutOverflow(const LayoutRect& rect)
 {
     LayoutUnit maxX = std::max(rect.maxX(), m_layoutOverflow.maxX());
     LayoutUnit maxY = std::max(rect.maxY(), m_layoutOverflow.maxY());
-    m_layoutOverflow.setX(std::min(rect.x(), m_layoutOverflow.x()));
-    m_layoutOverflow.setY(std::min(rect.y(), m_layoutOverflow.y()));
-    m_layoutOverflow.setWidth(maxX - m_layoutOverflow.x());
-    m_layoutOverflow.setHeight(maxY - m_layoutOverflow.y());
+    LayoutUnit minX = std::min(rect.x(), m_layoutOverflow.x());
+    LayoutUnit minY = std::min(rect.y(), m_layoutOverflow.y());
+    // In case the width/height is larger than LayoutUnit can represent, fix the right/bottom edge and shift the top/left ones
+    m_layoutOverflow.setWidth(maxX - minX);
+    m_layoutOverflow.setHeight(maxY - minY);
+    m_layoutOverflow.setX(maxX - m_layoutOverflow.width());
+    m_layoutOverflow.setY(maxY - m_layoutOverflow.height());
 }
 
 inline void RenderOverflow::addVisualOverflow(const LayoutRect& rect)