Update {virtual,override,final} to follow C++11 style in chromeos.

chromeos/timezone/timezone_request.h

Index: chromeos/timezone/timezone_request.h
diff --git a/chromeos/timezone/timezone_request.h b/chromeos/timezone/timezone_request.h
index 2433236b5e90a9912e5d95eea5d720a3561399a1..e90857823046cb641cc0675547719a99a7f8fd8b 100644
--- a/chromeos/timezone/timezone_request.h
+++ b/chromeos/timezone/timezone_request.h
@@ -75,7 +75,7 @@ class CHROMEOS_EXPORT TimeZoneRequest : private net::URLFetcherDelegate {
                   const Geoposition& geoposition,
                   base::TimeDelta retry_timeout);
 
-  virtual ~TimeZoneRequest();
+  ~TimeZoneRequest() override;
 
   // Initiates request.
   // Note: if request object is destroyed before callback is called,
@@ -94,7 +94,7 @@ class CHROMEOS_EXPORT TimeZoneRequest : private net::URLFetcherDelegate {
 
  private:
   // net::URLFetcherDelegate
-  virtual void OnURLFetchComplete(const net::URLFetcher* source) override;
+  void OnURLFetchComplete(const net::URLFetcher* source) override;
 
   // Start new request.
   void StartRequest();