Avoid N^2 walk placing renderers when building the render tree

Source/core/html/HTMLInputElement.cpp

Index: Source/core/html/HTMLInputElement.cpp
diff --git a/Source/core/html/HTMLInputElement.cpp b/Source/core/html/HTMLInputElement.cpp
index de999dda4948a273599990e3c4940783a158fd50..545c855e60b4e37fc57dbf2a023131597505b31a 100644
--- a/Source/core/html/HTMLInputElement.cpp
+++ b/Source/core/html/HTMLInputElement.cpp
@@ -1462,11 +1462,16 @@ void HTMLInputElement::didChangeForm()
     addToRadioButtonGroup();
 }
 
+void HTMLInputElement::addToRadioButtonGroupCallback(Element* element)
+{
+    toHTMLInputElement(element)->addToRadioButtonGroup();
+}
+
 Node::InsertionNotificationRequest HTMLInputElement::insertedInto(ContainerNode* insertionPoint)
 {
     HTMLTextFormControlElement::insertedInto(insertionPoint);
-    if (insertionPoint->inDocument() && !form())
-        addToRadioButtonGroup();
+    if (insertionPoint->inDocument() && !form() && checkedRadioButtons())
+        queueInsertionCallback(addToRadioButtonGroupCallback, this);
     resetListAttributeTargetObserver();
     return InsertionDone;
 }