Standardize usage of virtual/override/final in sync/

sync/internal_api/public/base/cancelation_signal_unittest.cc

Index: sync/internal_api/public/base/cancelation_signal_unittest.cc
diff --git a/sync/internal_api/public/base/cancelation_signal_unittest.cc b/sync/internal_api/public/base/cancelation_signal_unittest.cc
index e8b375dab6b992af7121eab43c273e7d2658afa1..58a35cc2eaa82b8dca21373636db87774290c942 100644
--- a/sync/internal_api/public/base/cancelation_signal_unittest.cc
+++ b/sync/internal_api/public/base/cancelation_signal_unittest.cc
@@ -18,7 +18,7 @@ namespace syncer {
 class BlockingTask : public CancelationObserver {
  public:
   BlockingTask(CancelationSignal* cancel_signal);
-  virtual ~BlockingTask();
+  ~BlockingTask() override;
 
   // Starts the |exec_thread_| and uses it to execute DoRun().
   void RunAsync(base::WaitableEvent* task_start_signal,
@@ -33,7 +33,7 @@ class BlockingTask : public CancelationObserver {
 
   // Implementation of CancelationObserver.
   // Wakes up the thread blocked in Run().
-  virtual void OnSignalReceived() override;
+  void OnSignalReceived() override;
 
   // Checks if we ever did successfully start waiting for |event_|.  Be careful
   // with this.  The flag itself is thread-unsafe, and the event that flips it
@@ -150,7 +150,7 @@ bool CancelationSignalTest::VerifyTaskNotStarted() {
 }
 
 class FakeCancelationObserver : public CancelationObserver {
-  virtual void OnSignalReceived() override { }
+  void OnSignalReceived() override {}
 };
 
 TEST(CancelationSignalTest_SingleThread, CheckFlags) {