Standardize usage of virtual/override/final in chrome/browser/sync/

chrome/browser/sync/glue/history_model_worker.cc

Index: chrome/browser/sync/glue/history_model_worker.cc
diff --git a/chrome/browser/sync/glue/history_model_worker.cc b/chrome/browser/sync/glue/history_model_worker.cc
index 87b5470a2526a1debcb8eb3fae7863bb83ea7c64..d9f87549b2b5ecb80a3ace880740cf04d1f10401 100644
--- a/chrome/browser/sync/glue/history_model_worker.cc
+++ b/chrome/browser/sync/glue/history_model_worker.cc
@@ -22,8 +22,8 @@ class WorkerTask : public history::HistoryDBTask {
       syncer::SyncerError* error)
     : work_(work), done_(done), error_(error) {}
 
-  virtual bool RunOnDBThread(history::HistoryBackend* backend,
-                             history::HistoryDatabase* db) override {
+  bool RunOnDBThread(history::HistoryBackend* backend,
+                     history::HistoryDatabase* db) override {
     *error_ = work_.Run();
     done_->Signal();
     return true;
@@ -31,10 +31,10 @@ class WorkerTask : public history::HistoryDBTask {
 
   // Since the DoWorkAndWaitUntilDone() is synchronous, we don't need to run
   // any code asynchronously on the main thread after completion.
-  virtual void DoneRunOnMainThread() override {}
+  void DoneRunOnMainThread() override {}
 
  protected:
-  virtual ~WorkerTask() {}
+  ~WorkerTask() override {}
 
   syncer::WorkCallback work_;
   WaitableEvent* done_;
@@ -46,16 +46,16 @@ class AddDBThreadObserverTask : public history::HistoryDBTask {
   explicit AddDBThreadObserverTask(base::Closure register_callback)
      : register_callback_(register_callback) {}
 
-  virtual bool RunOnDBThread(history::HistoryBackend* backend,
-                             history::HistoryDatabase* db) override {
+  bool RunOnDBThread(history::HistoryBackend* backend,
+                     history::HistoryDatabase* db) override {
     register_callback_.Run();
     return true;
   }
 
-  virtual void DoneRunOnMainThread() override {}
+  void DoneRunOnMainThread() override {}
 
  private:
-  virtual ~AddDBThreadObserverTask() {}
+  ~AddDBThreadObserverTask() override {}
 
   base::Closure register_callback_;
 };