Delete some unused code found by -Wunused-function

chrome/browser/extensions/settings/settings_sync_unittest.cc

Index: chrome/browser/extensions/settings/settings_sync_unittest.cc
diff --git a/chrome/browser/extensions/settings/settings_sync_unittest.cc b/chrome/browser/extensions/settings/settings_sync_unittest.cc
index 430cdd6e08138c2cb9b9663815f6453098f73e9f..e561cfc0bab020b7cf07bf35827951d7dfd7a298 100644
--- a/chrome/browser/extensions/settings/settings_sync_unittest.cc
+++ b/chrome/browser/extensions/settings/settings_sync_unittest.cc
@@ -194,12 +194,6 @@ class TestingValueStoreFactory : public SettingsStorageFactory {
   std::map<std::string, TestingValueStore*> created_;
 };
 
-void AssignSettingsService(syncer::SyncableService** dst,
-                           const SettingsFrontend* frontend,
-                           syncer::ModelType type) {
-  *dst = frontend->GetBackendForSync(type);
-}
-
 }  // namespace
 
 class ExtensionSettingsSyncTest : public testing::Test {