Implement select listbox using shadow DOM

Source/core/html/HTMLOptionElement.h

Index: Source/core/html/HTMLOptionElement.h
diff --git a/Source/core/html/HTMLOptionElement.h b/Source/core/html/HTMLOptionElement.h
index e5de12508fd1ac6de5ae723e32030f0c2075f788..31b91e187e9b6f602acc5ff21b4f6c6daafd9574 100644
--- a/Source/core/html/HTMLOptionElement.h
+++ b/Source/core/html/HTMLOptionElement.h
@@ -65,22 +65,18 @@ public:
     void setSelectedState(bool);
 
     HTMLFormElement* form() const;
-
-    bool isDisplayNone() const;
+    bool spatialNavigationFocused() const;
 
 private:
     explicit HTMLOptionElement(Document&);
 
-    virtual bool rendererIsFocusable() const OVERRIDE;
-    virtual bool rendererIsNeeded(const RenderStyle&) OVERRIDE { return false; }
+    virtual bool rendererIsFocusable() const OVERRIDE { return true; }
     virtual void attach(const AttachContext& = AttachContext()) OVERRIDE;
     virtual void detach(const AttachContext& = AttachContext()) OVERRIDE;
-
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
-
     virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
+    virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual void accessKeyAction(bool) OVERRIDE;
-
     virtual void childrenChanged(const ChildrenChange&) OVERRIDE;
 
     // <option> never has a renderer so we manually manage a cached style.
@@ -88,9 +84,12 @@ private:
     virtual RenderStyle* nonRendererStyle() const OVERRIDE;
     virtual PassRefPtr<RenderStyle> customStyleForRenderer() OVERRIDE;
     virtual void didRecalcStyle(StyleRecalcChange) OVERRIDE;
+    virtual void didAddUserAgentShadowRoot(ShadowRoot&) OVERRIDE;
 
     String collectOptionInnerText() const;
 
+    void updateLabel();
+
     bool m_disabled;
     bool m_isSelected;
     RefPtr<RenderStyle> m_style;