(blink) Propagate scrolling/marginwidth/marginheight property values to child frame.

Source/core/html/HTMLFrameOwnerElement.h

Index: Source/core/html/HTMLFrameOwnerElement.h
diff --git a/Source/core/html/HTMLFrameOwnerElement.h b/Source/core/html/HTMLFrameOwnerElement.h
index f0236a61cdf5a2dde0c7aeb34f669f7818437433..56e74e872c0347e375fe5471fa2a28ac3a40ca5b 100644
--- a/Source/core/html/HTMLFrameOwnerElement.h
+++ b/Source/core/html/HTMLFrameOwnerElement.h
@@ -59,8 +59,6 @@ public:
 
     Document* getSVGDocument(ExceptionState&) const;
 
-    virtual ScrollbarMode scrollingMode() const { return ScrollbarAuto; }
-
     virtual bool loadedNonEmptyDocument() const { return false; }
     virtual void didLoadNonEmptyDocument() { }
 
@@ -82,12 +80,18 @@ public:
     void dispatchLoad() override;
     SandboxFlags sandboxFlags() const override { return m_sandboxFlags; }
     void renderFallbackContent() override { }
+    ScrollbarMode scrollingMode() const override { return m_scrollingMode; }
+    int marginWidth() const override { return m_marginWidth; }
+    int marginHeight() const override { return m_marginHeight; }
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
     HTMLFrameOwnerElement(const QualifiedName& tagName, Document&);
     void setSandboxFlags(SandboxFlags);
+    void setScrollingMode(ScrollbarMode);
+    void setMarginWidth(int);
+    void setMarginHeight(int);
 
     bool loadOrRedirectSubframe(const KURL&, const AtomicString& frameName, bool replaceCurrentItem);
 
@@ -97,9 +101,14 @@ private:
 
     virtual ReferrerPolicy referrerPolicyAttribute() { return ReferrerPolicyDefault; }
 
+    void frameOwnerPropertiesChanged();
+
     RawPtrWillBeMember<Frame> m_contentFrame;
     RefPtrWillBeMember<Widget> m_widget;
     SandboxFlags m_sandboxFlags;
+    ScrollbarMode m_scrollingMode;
+    int m_marginWidth;
+    int m_marginHeight;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(HTMLFrameOwnerElement, isFrameOwnerElement());