Coverity: Pass parameters by reference.

chrome/browser/sync/glue/preference_model_associator.h

Index: chrome/browser/sync/glue/preference_model_associator.h
diff --git a/chrome/browser/sync/glue/preference_model_associator.h b/chrome/browser/sync/glue/preference_model_associator.h
index 15f30013e57aac9422ea81296b2e08c097c3371c..444c03a31c39bb20b3a3015505995a7b77c44d2b 100644
--- a/chrome/browser/sync/glue/preference_model_associator.h
+++ b/chrome/browser/sync/glue/preference_model_associator.h
@@ -76,14 +76,14 @@ class PreferenceModelAssociator
   }
 
   // Not implemented.
-  virtual bool InitSyncNodeFromChromeId(std::string node_id,
+  virtual bool InitSyncNodeFromChromeId(const std::string& node_id,
                                         sync_api::BaseNode* sync_node) {
     return false;
   }
 
   // Returns the sync id for the given preference name, or sync_api::kInvalidId
   // if the preference name is not associated to any sync id.
-  virtual int64 GetSyncIdFromChromeId(std::string node_id);
+  virtual int64 GetSyncIdFromChromeId(const std::string& node_id);
 
   // Associates the given preference name with the given sync id.
   virtual void Associate(const PrefService::Preference* node, int64 sync_id);