Implement select listbox using shadow DOM

Source/core/html/HTMLOptionElement.cpp

Index: Source/core/html/HTMLOptionElement.cpp
diff --git a/Source/core/html/HTMLOptionElement.cpp b/Source/core/html/HTMLOptionElement.cpp
index 79239f43d70034107d2d61f13d3d2e29703a3344..4814944c6edc9f56468ab48ace6aad63fb1356ca 100644
--- a/Source/core/html/HTMLOptionElement.cpp
+++ b/Source/core/html/HTMLOptionElement.cpp
@@ -34,7 +34,9 @@
 #include "core/dom/NodeTraversal.h"
 #include "core/dom/ScriptLoader.h"
 #include "core/dom/Text.h"
+#include "core/dom/shadow/ShadowRoot.h"
 #include "core/html/HTMLDataListElement.h"
+#include "core/html/HTMLOptGroupElement.h"
 #include "core/html/HTMLSelectElement.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/rendering/RenderTheme.h"
@@ -97,8 +99,11 @@ void HTMLOptionElement::detach(const AttachContext& context)
 
 bool HTMLOptionElement::rendererIsFocusable() const
 {
-    // Option elements do not have a renderer so we check the renderStyle instead.
-    return renderStyle() && renderStyle()->display() != NONE;
+    HTMLSelectElement* selectElement = ownerSelectElement();
+    if (!selectElement || selectElement->usesMenuList()) {
+        return !isDisplayNone();
+    }
+    return HTMLElement::rendererIsFocusable();
 }
 
 String HTMLOptionElement::text() const
@@ -188,6 +193,8 @@ void HTMLOptionElement::parseAttribute(const QualifiedName& name, const AtomicSt
     } else if (name == selectedAttr) {
         if (bool willBeSelected = !value.isNull())
             setSelected(willBeSelected);
+    } else if (name == labelAttr) {
+        updateLabel();
     } else
         HTMLElement::parseAttribute(name, value);
 }
@@ -251,6 +258,7 @@ void HTMLOptionElement::childrenChanged(bool changedByParser, Node* beforeChange
         dataList->optionElementChildrenChanged();
     else if (HTMLSelectElement* select = ownerSelectElement())
         select->optionElementChildrenChanged();
+    updateLabel();
     HTMLElement::childrenChanged(changedByParser, beforeChange, afterChange, childCountDelta);
 }
 
@@ -277,6 +285,12 @@ void HTMLOptionElement::setLabel(const AtomicString& label)
     setAttribute(labelAttr, label);
 }
 
+bool HTMLOptionElement::rendererIsNeeded(const RenderStyle&)
+{
+    HTMLSelectElement* select = ownerSelectElement();
+    return select && !select->usesMenuList() && !isDisplayNone();
+}
+
 void HTMLOptionElement::updateNonRenderStyle()
 {
     bool oldDisplayNoneStatus = isDisplayNone();
@@ -329,6 +343,7 @@ bool HTMLOptionElement::isDisabledFormControl() const
 
 Node::InsertionNotificationRequest HTMLOptionElement::insertedInto(ContainerNode* insertionPoint)
 {
+    HTMLElement::insertedInto(insertionPoint);
     if (HTMLSelectElement* select = ownerSelectElement()) {
         select->setRecalcListItems();
         // Do not call selected() since calling updateListItemSelectedStates()
@@ -339,8 +354,29 @@ Node::InsertionNotificationRequest HTMLOptionElement::insertedInto(ContainerNode
             select->optionSelectionStateChanged(this, true);
         select->scrollToSelection();
     }
+    return insertionPoint->inDocument() ? InsertionShouldCallDidNotifySubtreeInsertions : InsertionDone;

[keishi, 2014/06/22 11:59:55]

We can't call ensureUserAgentShadow inside insertedInto because of
NoEventDispatchAssertion.

+}
 
-    return HTMLElement::insertedInto(insertionPoint);
+void HTMLOptionElement::didNotifySubtreeInsertionsToDocument()
+{
+    updateView();
+}
+
+void HTMLOptionElement::updateView()
+{
+    HTMLSelectElement* select = ownerSelectElement();
+    if (select && !select->usesMenuList())

[keishi, 2014/06/22 11:59:55]

Only create shadow root when shown in a listbox.

+        ensureUserAgentShadowRoot();
+    else if (userAgentShadowRoot())
+        userAgentShadowRoot()->detach();
+}
+
+void HTMLOptionElement::removedFrom(ContainerNode* insertionPoint)
+{
+    HTMLSelectElement* select = Traversal<HTMLSelectElement>::firstAncestorOrSelf(*insertionPoint);
+    if (select)
+        return select->optionRemoved(this);
+    HTMLElement::removedFrom(insertionPoint);
 }
 
 String HTMLOptionElement::collectOptionInnerText() const
@@ -378,4 +414,16 @@ bool HTMLOptionElement::isDisplayNone() const
     return style && style->display() == NONE;
 }
 
+void HTMLOptionElement::updateLabel()
+{
+    ShadowRoot* root = userAgentShadowRoot();
+    if (!root)
+        return;
+    Text* const textNode = toText(root->firstChild());
+    if (textNode)
+        textNode->replaceWholeText(textIndentedToRespectGroupLabel());
+    else
+        root->appendChild(Text::create(document(), textIndentedToRespectGroupLabel()), ASSERT_NO_EXCEPTION);
+}
+
 } // namespace WebCore