Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/inspector/InspectorResourceAgent.cpp

Index: Source/core/inspector/InspectorResourceAgent.cpp
diff --git a/Source/core/inspector/InspectorResourceAgent.cpp b/Source/core/inspector/InspectorResourceAgent.cpp
index ea683bc22044a4f969904d3896843d56baa9088b..13fd69e2c6379aa953856482193b49b02fede9b1 100644
--- a/Source/core/inspector/InspectorResourceAgent.cpp
+++ b/Source/core/inspector/InspectorResourceAgent.cpp
@@ -157,7 +157,7 @@ public:
 private:
     void dispose()
     {
-        m_loader = 0;
+        m_loader = nullptr;
         delete this;
     }
 
@@ -231,8 +231,7 @@ static PassRefPtr<TypeBuilder::Network::Request> buildObjectForResourceRequest(c
 static PassRefPtr<TypeBuilder::Network::Response> buildObjectForResourceResponse(const ResourceResponse& response, DocumentLoader* loader)
 {
     if (response.isNull())
-        return 0;
-
+        return nullptr;
 
     double status;
     String statusText;