Make sure the rootNode of a LiveNodeListBase is always a ContainerNode

Source/core/html/HTMLFormControlsCollection.cpp

Index: Source/core/html/HTMLFormControlsCollection.cpp
diff --git a/Source/core/html/HTMLFormControlsCollection.cpp b/Source/core/html/HTMLFormControlsCollection.cpp
index 16a027360c9eb5ed987168eaa93b9190fb22b8e6..62126839fe4f594e73761f6d9f654e4d1e01cbb8 100644
--- a/Source/core/html/HTMLFormControlsCollection.cpp
+++ b/Source/core/html/HTMLFormControlsCollection.cpp
@@ -35,7 +35,7 @@ using namespace HTMLNames;
 // Since the collections are to be "live", we have to do the
 // calculation every time if anything has changed.
 
-HTMLFormControlsCollection::HTMLFormControlsCollection(Node* ownerNode)
+HTMLFormControlsCollection::HTMLFormControlsCollection(ContainerNode* ownerNode)
     : HTMLCollection(ownerNode, FormControls, OverridesItemAfter)
     , m_cachedElement(0)
     , m_cachedElementOffsetInArray(0)
@@ -44,7 +44,7 @@ HTMLFormControlsCollection::HTMLFormControlsCollection(Node* ownerNode)
     ScriptWrappable::init(this);
 }
 
-PassRefPtr<HTMLFormControlsCollection> HTMLFormControlsCollection::create(Node* ownerNode, CollectionType)
+PassRefPtr<HTMLFormControlsCollection> HTMLFormControlsCollection::create(ContainerNode* ownerNode, CollectionType)
 {
     return adoptRef(new HTMLFormControlsCollection(ownerNode));
 }