Adding Element.closest() API

Source/core/dom/SelectorQuery.cpp

Index: Source/core/dom/SelectorQuery.cpp
diff --git a/Source/core/dom/SelectorQuery.cpp b/Source/core/dom/SelectorQuery.cpp
index b097dd0c653e290ee34defe00a34f24e10d14443..455b1731cf28f8c74f7c78ed1b4cb3d7ae58b85f 100644
--- a/Source/core/dom/SelectorQuery.cpp
+++ b/Source/core/dom/SelectorQuery.cpp
@@ -136,6 +136,18 @@ bool SelectorDataList::matches(Element& targetElement) const
     return false;
 }
 
+Element* SelectorDataList::closest(Element& targetElement) const
+{
+    unsigned selectorCount = m_selectors.size();
+    for (Element* currentElement = &targetElement; currentElement; currentElement = currentElement->parentElement()) {
+        for (unsigned i = 0; i < selectorCount; ++i) {
+            if (selectorMatches(*m_selectors[i], *currentElement, targetElement))
+                return currentElement;
+        }
+    }
+    return nullptr;
+}
+
 PassRefPtrWillBeRawPtr<StaticElementList> SelectorDataList::queryAll(ContainerNode& rootNode) const
 {
     WillBeHeapVector<RefPtrWillBeMember<Element> > result;
@@ -481,6 +493,11 @@ bool SelectorQuery::matches(Element& element) const
     return m_selectors.matches(element);
 }
 
+Element* SelectorQuery::closest(Element& element) const
+{
+    return m_selectors.closest(element);
+}
+
 PassRefPtrWillBeRawPtr<StaticElementList> SelectorQuery::queryAll(ContainerNode& rootNode) const
 {
     return m_selectors.queryAll(rootNode);