Rewrite scoped_ptr<T>(NULL) to use the default ctor in chrome/.

chrome/browser/extensions/api/declarative/declarative_rule.h

Index: chrome/browser/extensions/api/declarative/declarative_rule.h
diff --git a/chrome/browser/extensions/api/declarative/declarative_rule.h b/chrome/browser/extensions/api/declarative/declarative_rule.h
index bdc36fef0b00fe954fb16ff0942f866c7e5862ad..11d223ab733c246b519dd45b109870761d97960f 100644
--- a/chrome/browser/extensions/api/declarative/declarative_rule.h
+++ b/chrome/browser/extensions/api/declarative/declarative_rule.h
@@ -299,7 +299,7 @@ DeclarativeConditionSet<ConditionT>::Create(
     scoped_ptr<ConditionT> condition =
         ConditionT::Create(url_matcher_condition_factory, **i, error);
     if (!error->empty())
-      return scoped_ptr<DeclarativeConditionSet>(NULL);
+      return scoped_ptr<DeclarativeConditionSet>();
     result.push_back(make_linked_ptr(condition.release()));
   }
 
@@ -359,7 +359,7 @@ DeclarativeActionSet<ActionT>::Create(
     scoped_refptr<const ActionT> action =
         ActionT::Create(**i, error, bad_message);
     if (!error->empty() || *bad_message)
-      return scoped_ptr<DeclarativeActionSet>(NULL);
+      return scoped_ptr<DeclarativeActionSet>();
     result.push_back(action);
   }