Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/xml/XSLTProcessor.cpp

Index: Source/core/xml/XSLTProcessor.cpp
diff --git a/Source/core/xml/XSLTProcessor.cpp b/Source/core/xml/XSLTProcessor.cpp
index dbb572d067a188e6d78c96178fab5c5d924dc5cf..7194289a33ddcd8203743af8ff851e4973622245 100644
--- a/Source/core/xml/XSLTProcessor.cpp
+++ b/Source/core/xml/XSLTProcessor.cpp
@@ -104,20 +104,20 @@ PassRefPtr<Document> XSLTProcessor::createDocumentFromSource(const String& sourc
 PassRefPtr<Document> XSLTProcessor::transformToDocument(Node* sourceNode)
 {
     if (!sourceNode)
-        return 0;
+        return nullptr;
 
     String resultMIMEType;
     String resultString;
     String resultEncoding;
     if (!transformToString(sourceNode, resultMIMEType, resultString, resultEncoding))
-        return 0;
+        return nullptr;
     return createDocumentFromSource(resultString, resultEncoding, resultMIMEType, sourceNode, 0);
 }
 
 PassRefPtr<DocumentFragment> XSLTProcessor::transformToFragment(Node* sourceNode, Document* outputDoc)
 {
     if (!sourceNode || !outputDoc)
-        return 0;
+        return nullptr;
 
     String resultMIMEType;
     String resultString;
@@ -128,7 +128,7 @@ PassRefPtr<DocumentFragment> XSLTProcessor::transformToFragment(Node* sourceNode
         resultMIMEType = "text/html";
 
     if (!transformToString(sourceNode, resultMIMEType, resultString, resultEncoding))
-        return 0;
+        return nullptr;
     return createFragmentForTransformToFragment(resultString, resultMIMEType, *outputDoc);
 }