Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/core/plugins/DOMPlugin.cpp

Index: Source/core/plugins/DOMPlugin.cpp
diff --git a/Source/core/plugins/DOMPlugin.cpp b/Source/core/plugins/DOMPlugin.cpp
index 67492d6100798d2e8ff65b7bb7132667c6b740e9..96bc9b59af1c69d2402e7514713ef254a0a28196 100644
--- a/Source/core/plugins/DOMPlugin.cpp
+++ b/Source/core/plugins/DOMPlugin.cpp
@@ -61,7 +61,7 @@ unsigned DOMPlugin::length() const
 PassRefPtrWillBeRawPtr<DOMMimeType> DOMPlugin::item(unsigned index)
 {
     if (index >= pluginInfo().mimes.size())
-        return 0;
+        return nullptr;
 
     const MimeClassInfo& mime = pluginInfo().mimes[index];
 
@@ -70,7 +70,7 @@ PassRefPtrWillBeRawPtr<DOMMimeType> DOMPlugin::item(unsigned index)
         if (mimes[i] == mime && m_pluginData->mimePluginIndices()[i] == m_index)
             return DOMMimeType::create(m_pluginData.get(), m_frame, i).get();
     }
-    return 0;
+    return nullptr;
 }
 
 bool DOMPlugin::canGetItemsForName(const AtomicString& propertyName)
@@ -88,7 +88,7 @@ PassRefPtrWillBeRawPtr<DOMMimeType> DOMPlugin::namedItem(const AtomicString& pro
     for (unsigned i = 0; i < mimes.size(); ++i)
         if (mimes[i].type == propertyName)
             return DOMMimeType::create(m_pluginData.get(), m_frame, i).get();
-    return 0;
+    return nullptr;
 }
 
 } // namespace WebCore