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

chrome/browser/chromeos/login/signin/merge_session_throttle.h

Index: chrome/browser/chromeos/login/signin/merge_session_throttle.h
diff --git a/chrome/browser/chromeos/login/signin/merge_session_throttle.h b/chrome/browser/chromeos/login/signin/merge_session_throttle.h
index c0298ad98bcfd6cfb665a4759db40dda5fa2771b..d87fe9d15dff18883f4de4984c49edfa6b1f8750 100644
--- a/chrome/browser/chromeos/login/signin/merge_session_throttle.h
+++ b/chrome/browser/chromeos/login/signin/merge_session_throttle.h
@@ -37,11 +37,11 @@ class MergeSessionThrottle
 
   explicit MergeSessionThrottle(net::URLRequest* request,
                                 content::ResourceType resource_type);
-  virtual ~MergeSessionThrottle();
+  ~MergeSessionThrottle() override;
 
   // content::ResourceThrottle implementation:
-  virtual void WillStartRequest(bool* defer) override;
-  virtual const char* GetNameForLogging() const override;
+  void WillStartRequest(bool* defer) override;
+  const char* GetNameForLogging() const override;
 
   // Checks if session is already merged.
   static bool AreAllSessionMergedAlready();