Standardize usage of virtual/override/final specifiers.

ui/app_list/search/history_data_store_unittest.cc

Index: ui/app_list/search/history_data_store_unittest.cc
diff --git a/ui/app_list/search/history_data_store_unittest.cc b/ui/app_list/search/history_data_store_unittest.cc
index 4e7c2a7bc68844e534a03b1f8cc5b9e9d6df71b4..26890f46619f1eb7c2c81968b10dfc2247bcb523 100644
--- a/ui/app_list/search/history_data_store_unittest.cc
+++ b/ui/app_list/search/history_data_store_unittest.cc
@@ -42,14 +42,14 @@ std::string GetDataContent(const HistoryData::Data& data) {
 class HistoryDataStoreTest : public testing::Test {
  public:
   HistoryDataStoreTest() {}
-  virtual ~HistoryDataStoreTest() {}
+  ~HistoryDataStoreTest() override {}
 
   // testing::Test overrides:
-  virtual void SetUp() override {
+  void SetUp() override {
     worker_pool_ = new base::SequencedWorkerPool(1, "AppLauncherTest");
     ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
   }
-  virtual void TearDown() override {
+  void TearDown() override {
     // Release |store_| while ui loop is still running.
     store_ = NULL;
   }