Take CSS Clip and contain: paint into account when computing visual rects.

third_party/WebKit/Source/core/layout/LayoutBox.h

Index: third_party/WebKit/Source/core/layout/LayoutBox.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.h b/third_party/WebKit/Source/core/layout/LayoutBox.h
index 8b8c257bfa5cdb863001c3daeb96e65a70c0580a..e92d002234bfd6f55aee9324e65d3e63b973f65e 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.h
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.h
@@ -796,6 +796,9 @@ public:
     virtual bool hasControlClip() const { return false; }
     virtual LayoutRect controlClipRect(const LayoutPoint&) const { return LayoutRect(); }
 
+    // Returns the combination of overflow clip, contain: paint clip and CSS clip for this object, in local space.
+    LayoutRect clippingRect() const;
+
     virtual void paintBoxDecorationBackground(const PaintInfo&, const LayoutPoint&) const;
     virtual void paintMask(const PaintInfo&, const LayoutPoint&) const;
     void imageChanged(WrappedImagePtr, const IntRect* = nullptr) override;