Cleanup HistoryService and HistoryBackend interface

chrome/browser/sync/profile_sync_service_typed_url_unittest.cc

Index: chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
diff --git a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
index 07f7ae1a5aab638b028652eaef940a7a5dc680a8..c6fb8a809ac3e7277ad99d0c6e7d84d100bd3a2e 100644
--- a/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
+++ b/chrome/browser/sync/profile_sync_service_typed_url_unittest.cc
@@ -87,7 +87,7 @@ static const int EXPIRED_VISIT = -1;
 
 class HistoryBackendMock : public HistoryBackend {
  public:
-  HistoryBackendMock() : HistoryBackend(base::FilePath(), NULL, NULL) {}
+  HistoryBackendMock() : HistoryBackend(nullptr, nullptr) {}
   virtual bool IsExpiredVisitTime(const base::Time& time) override {
     return time.ToInternalValue() == EXPIRED_VISIT;
   }