Implement <select> Popup Menu using PagePopup

Source/core/html/HTMLSelectElement.cpp

Index: Source/core/html/HTMLSelectElement.cpp
diff --git a/Source/core/html/HTMLSelectElement.cpp b/Source/core/html/HTMLSelectElement.cpp
index 1c1dc110fdc428bdd5f5ab7fa0d90137499f579e..8376127b45993d73de2268c53d4c8a215c005ca0 100644
--- a/Source/core/html/HTMLSelectElement.cpp
+++ b/Source/core/html/HTMLSelectElement.cpp
@@ -1204,10 +1204,6 @@ void HTMLSelectElement::handlePopupOpenKeyboardEvent(Event* event)
     saveLastSelection();
     if (RenderMenuList* menuList = toRenderMenuList(renderer()))
         menuList->showPopup();
-    int index = selectedIndex();
-    ASSERT(index >= 0);
-    ASSERT_WITH_SECURITY_IMPLICATION(index < static_cast<int>(listItems().size()));
-    setSelectedIndex(index);
     event->setDefaultHandled();
     return;
 }
@@ -1762,7 +1758,7 @@ void HTMLSelectElement::trace(Visitor* visitor)
 void HTMLSelectElement::didAddUserAgentShadowRoot(ShadowRoot& root)
 {
     RefPtrWillBeRawPtr<HTMLContentElement> content = HTMLContentElement::create(document());
-    content->setAttribute(selectAttr, "option,optgroup");
+    content->setAttribute(selectAttr, "option,optgroup,hr");
     root.appendChild(content);
 }