Use nullptr_t for RefPtr, PassRefPtr and RawPtr.

Source/modules/webdatabase/DOMWindowWebDatabase.cpp

Index: Source/modules/webdatabase/DOMWindowWebDatabase.cpp
diff --git a/Source/modules/webdatabase/DOMWindowWebDatabase.cpp b/Source/modules/webdatabase/DOMWindowWebDatabase.cpp
index bc1dcd51c28e3c57bee8e0b500fc58f3070673f2..ecb7b6f72b4d309c7ec83c97df79c4ac55270866 100644
--- a/Source/modules/webdatabase/DOMWindowWebDatabase.cpp
+++ b/Source/modules/webdatabase/DOMWindowWebDatabase.cpp
@@ -43,9 +43,9 @@ namespace WebCore {
 PassRefPtr<Database> DOMWindowWebDatabase::openDatabase(DOMWindow& window, const String& name, const String& version, const String& displayName, unsigned long estimatedSize, PassOwnPtr<DatabaseCallback> creationCallback, ExceptionState& exceptionState)
 {
     if (!window.isCurrentlyDisplayedInFrame())
-        return 0;
+        return nullptr;
 
-    RefPtr<Database> database = 0;
+    RefPtr<Database> database = nullptr;
     DatabaseManager& dbManager = DatabaseManager::manager();
     DatabaseError error = DatabaseError::None;
     if (RuntimeEnabledFeatures::databaseEnabled() && window.document()->securityOrigin()->canAccessDatabase()) {