Cleanup HistoryService and HistoryBackend interface

chrome/browser/history/history_unittest.cc

Index: chrome/browser/history/history_unittest.cc
diff --git a/chrome/browser/history/history_unittest.cc b/chrome/browser/history/history_unittest.cc
index 6a3cf00506b85c02411162fe751b0275434a8f86..d110d7b0727341d9254ea757ecd30c2569180e5f 100644
--- a/chrome/browser/history/history_unittest.cc
+++ b/chrome/browser/history/history_unittest.cc
@@ -136,8 +136,7 @@ class HistoryBackendDBTest : public HistoryUnitTestBase {
   // Creates the HistoryBackend and HistoryDatabase on the current thread,
   // assigning the values to backend_ and db_.
   void CreateBackendAndDatabase() {
-    backend_ =
-        new HistoryBackend(history_dir_, new BackendDelegate(this), NULL);
+    backend_ = new HistoryBackend(new BackendDelegate(this), nullptr);
     backend_->Init(std::string(), false,
                    HistoryDatabaseParamsForPath(history_dir_));
     db_ = backend_->db_.get();