Implement select listbox using shadow DOM

Source/core/html/HTMLOptGroupElement.h

Index: Source/core/html/HTMLOptGroupElement.h
diff --git a/Source/core/html/HTMLOptGroupElement.h b/Source/core/html/HTMLOptGroupElement.h
index a6674e0784ec591a8e18c857fade24a529f30bd5..78a2ddddf4ce69ae89211144ff862a979add6b9f 100644
--- a/Source/core/html/HTMLOptGroupElement.h
+++ b/Source/core/html/HTMLOptGroupElement.h
@@ -32,21 +32,24 @@ class HTMLSelectElement;
 
 class HTMLOptGroupElement FINAL : public HTMLElement {
 public:
-    DECLARE_NODE_FACTORY(HTMLOptGroupElement);
+    static PassRefPtrWillBeRawPtr<HTMLOptGroupElement> create(Document&);
+    virtual void trace(Visitor*) OVERRIDE;
 
     virtual bool isDisabledFormControl() const OVERRIDE;
     HTMLSelectElement* ownerSelectElement() const;
 
     String groupLabelText() const;
+    LayoutUnit groupLabelHeight() const;
 
     bool isDisplayNone() const;
+    void updateView();
 
 private:
     explicit HTMLOptGroupElement(Document&);
 
     virtual bool rendererIsFocusable() const OVERRIDE;
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) 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;
 
@@ -54,13 +57,18 @@ private:
 
     virtual void accessKeyAction(bool sendMouseEvents) OVERRIDE;
 
-    // <optgroup> never has a renderer so we manually manage a cached style.
+    // <optgroup> might not have a renderer so we manually manage a cached style.
     void updateNonRenderStyle();
     virtual RenderStyle* nonRendererStyle() const OVERRIDE;
     virtual PassRefPtr<RenderStyle> customStyleForRenderer() OVERRIDE;
+    virtual void didAddUserAgentShadowRoot(ShadowRoot&) OVERRIDE;
+    virtual InsertionNotificationRequest insertedInto(ContainerNode*) OVERRIDE;
+    virtual void didNotifySubtreeInsertionsToDocument() OVERRIDE;
 
     void recalcSelectOptions();
+    void updateGroupLabel();
 
+    RawPtrWillBeMember<HTMLDivElement> m_groupLabelElement;
     RefPtr<RenderStyle> m_style;
 };