Remove year+ old migration support of "session.urls_to_restore_on_startup".

components/password_manager/sync/browser/password_manager_setting_migrator_service_unittest.cc

Index: components/password_manager/sync/browser/password_manager_setting_migrator_service_unittest.cc
diff --git a/components/password_manager/sync/browser/password_manager_setting_migrator_service_unittest.cc b/components/password_manager/sync/browser/password_manager_setting_migrator_service_unittest.cc
index d5f4e1299d5041084118e0c1b3841b5c8ba87a6b..580a6cddfaf6ef3846f601eb5bc02a750d043a39 100644
--- a/components/password_manager/sync/browser/password_manager_setting_migrator_service_unittest.cc
+++ b/components/password_manager/sync/browser/password_manager_setting_migrator_service_unittest.cc
@@ -150,16 +150,6 @@ class TestPrefModelAssociatorClient
     return false;
   }
 
-  bool IsMigratedPreference(const std::string& new_pref_name,
-                            std::string* old_pref_name) const override {
-    return false;
-  }
-
-  bool IsOldMigratedPreference(const std::string& old_pref_name,
-                               std::string* new_pref_name) const override {
-    return false;
-  }
-
  private:
   DISALLOW_COPY_AND_ASSIGN(TestPrefModelAssociatorClient);
 };