Use "unsigned" rather than "unsigned long" for C++ code interacting with WebIDL's "unsigned long".

Source/core/xml/XPathResult.cpp

Index: Source/core/xml/XPathResult.cpp
diff --git a/Source/core/xml/XPathResult.cpp b/Source/core/xml/XPathResult.cpp
index 2dcc058f1ec4579ef1599071ab6b3501f0e6d1f8..689d87270a6d246c18a73b785c848e078101875b 100644
--- a/Source/core/xml/XPathResult.cpp
+++ b/Source/core/xml/XPathResult.cpp
@@ -173,7 +173,7 @@ bool XPathResult::invalidIteratorState() const
     return m_document->domTreeVersion() != m_domTreeVersion;
 }
 
-unsigned long XPathResult::snapshotLength(ExceptionState& exceptionState) const
+unsigned XPathResult::snapshotLength(ExceptionState& exceptionState) const
 {
     if (resultType() != UNORDERED_NODE_SNAPSHOT_TYPE && resultType() != ORDERED_NODE_SNAPSHOT_TYPE) {
         exceptionState.throwTypeError("The result type is not a snapshot.");
@@ -205,7 +205,7 @@ Node* XPathResult::iterateNext(ExceptionState& exceptionState)
     return node;
 }
 
-Node* XPathResult::snapshotItem(unsigned long index, ExceptionState& exceptionState)
+Node* XPathResult::snapshotItem(unsigned index, ExceptionState& exceptionState)
 {
     if (resultType() != UNORDERED_NODE_SNAPSHOT_TYPE && resultType() != ORDERED_NODE_SNAPSHOT_TYPE) {
         exceptionState.throwTypeError("The result type is not a snapshot.");