Migrate startup URLs pref.

chrome/browser/prefs/pref_model_associator.h

Index: chrome/browser/prefs/pref_model_associator.h
diff --git a/chrome/browser/prefs/pref_model_associator.h b/chrome/browser/prefs/pref_model_associator.h
index 539d38a301c9b71d15547053c8c8093cd5268cd0..3e70bd117541f18a9cadb1613d583c7c168308e2 100644
--- a/chrome/browser/prefs/pref_model_associator.h
+++ b/chrome/browser/prefs/pref_model_associator.h
@@ -118,12 +118,15 @@ class PrefModelAssociator
   // with ours and append a new UPDATE SyncChange to |sync_changes|. If
   // sync_pref is not set, we append an ADD SyncChange to |sync_changes| with
   // the current preference data.
+  // |migrated_preference_list| points to a vector that may be updated with a
+  // string containing the old name of the preference described by |pref_name|.
   // Note: We do not modify the sync data for preferences that are either
   // controlled by policy (are not user modifiable) or have their default value
   // (are not user controlled).
   void InitPrefAndAssociate(const syncer::SyncData& sync_pref,
                             const std::string& pref_name,
-                            syncer::SyncChangeList* sync_changes);
+                            syncer::SyncChangeList* sync_changes,
+                            SyncDataMap* migrated_preference_list);
 
   static base::Value* MergeListValues(
       const base::Value& from_value, const base::Value& to_value);