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 65e1a2394b84a80e0c9830f0733ae5e09ac76152..a67359afd47c6487ae98fdae1e38a9b9d6084e7e 100644
--- a/Source/core/html/HTMLOptionElement.h
+++ b/Source/core/html/HTMLOptionElement.h
@@ -67,18 +67,21 @@ public:
     HTMLFormElement* form() const;
 
     bool isDisplayNone() const;
+    void updateView();
 
 private:
     explicit HTMLOptionElement(Document&);
 
     virtual bool rendererIsFocusable() const OVERRIDE;
-    virtual bool rendererIsNeeded(const RenderStyle&) OVERRIDE { return false; }
+    virtual bool rendererIsNeeded(const RenderStyle&) OVERRIDE;
     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 didNotifySubtreeInsertionsToDocument() OVERRIDE;
+    virtual void removedFrom(ContainerNode*) OVERRIDE;
     virtual void accessKeyAction(bool) OVERRIDE;
 
     virtual void childrenChanged(bool changedByParser = false, Node* beforeChange = 0, Node* afterChange = 0, int childCountDelta = 0) OVERRIDE;
@@ -88,9 +91,12 @@ 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;