Fix bottom padding on flex boxes with overflow.

Source/core/rendering/RenderFlexibleBox.cpp

Index: Source/core/rendering/RenderFlexibleBox.cpp
diff --git a/Source/core/rendering/RenderFlexibleBox.cpp b/Source/core/rendering/RenderFlexibleBox.cpp
index d8dfa98834e550388609261a09d348f2df5d60f6..e62118127ede08103e8459a02c41682165b3be74 100644
--- a/Source/core/rendering/RenderFlexibleBox.cpp
+++ b/Source/core/rendering/RenderFlexibleBox.cpp
@@ -341,7 +341,7 @@ LayoutUnit RenderFlexibleBox::clientLogicalBottomAfterRepositioning()
         LayoutUnit childLogicalBottom = logicalTopForChild(child) + logicalHeightForChild(child) + marginAfterForChild(child);
         maxChildLogicalBottom = std::max(maxChildLogicalBottom, childLogicalBottom);
     }
-    return std::max(clientLogicalBottom(), maxChildLogicalBottom);
+    return std::max(clientLogicalBottom(), maxChildLogicalBottom + paddingAfter());
 }
 
 bool RenderFlexibleBox::hasOrthogonalFlow(RenderBox* child) const