Make sure the root node of selector queries is a ContainerNode

Source/core/dom/ContainerNode.cpp

Index: Source/core/dom/ContainerNode.cpp
diff --git a/Source/core/dom/ContainerNode.cpp b/Source/core/dom/ContainerNode.cpp
index 7b16890ad209ea0002b0d0b750a6c7fd749dd882..2f162a0cb0305a279256f431cf7689ece6d524c5 100644
--- a/Source/core/dom/ContainerNode.cpp
+++ b/Source/core/dom/ContainerNode.cpp
@@ -35,6 +35,7 @@
 #include "core/dom/NodeRareData.h"
 #include "core/dom/NodeRenderStyle.h"
 #include "core/dom/NodeTraversal.h"
+#include "core/dom/SelectorQuery.h"
 #include "core/events/MutationEvent.h"
 #include "core/events/ThreadLocalEventNames.h"
 #include "core/html/HTMLCollection.h"
@@ -910,6 +911,32 @@ Node *ContainerNode::childNode(unsigned index) const
     return n;
 }
 
+PassRefPtr<Element> ContainerNode::querySelector(const AtomicString& selectors, ExceptionState& exceptionState)
+{
+    if (selectors.isEmpty()) {
+        exceptionState.throwDOMException(SyntaxError, "The provided selector is empty.");
+        return 0;
+    }
+
+    SelectorQuery* selectorQuery = document().selectorQueryCache().add(selectors, document(), exceptionState);
+    if (!selectorQuery)
+        return 0;
+    return selectorQuery->queryFirst(*this);
+}
+
+PassRefPtr<NodeList> ContainerNode::querySelectorAll(const AtomicString& selectors, ExceptionState& exceptionState)
+{
+    if (selectors.isEmpty()) {
+        exceptionState.throwDOMException(SyntaxError, "The provided selector is empty.");
+        return 0;
+    }
+
+    SelectorQuery* selectorQuery = document().selectorQueryCache().add(selectors, document(), exceptionState);
+    if (!selectorQuery)
+        return 0;
+    return selectorQuery->queryAll(*this);
+}
+
 static void dispatchChildInsertionEvents(Node& child)
 {
     if (child.isInShadowTree())