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

chrome/browser/search/contextual_search_promo_source_android.h

Index: chrome/browser/search/contextual_search_promo_source_android.h
diff --git a/chrome/browser/search/contextual_search_promo_source_android.h b/chrome/browser/search/contextual_search_promo_source_android.h
index 1a2319f68bc924b0abd2a969e68075e774b4e97e..4ed5bbbf9bae80c2996ffdda055e75d0fcca7519 100644
--- a/chrome/browser/search/contextual_search_promo_source_android.h
+++ b/chrome/browser/search/contextual_search_promo_source_android.h
@@ -13,20 +13,19 @@
 class ContextualSearchPromoSourceAndroid : public content::URLDataSource {
  public:
   ContextualSearchPromoSourceAndroid();
-  virtual ~ContextualSearchPromoSourceAndroid();
+  ~ContextualSearchPromoSourceAndroid() override;
 
  protected:
   // Overridden from content::URLDataSource:
-  virtual void StartDataRequest(
+  void StartDataRequest(
       const std::string& path_and_query,
       int render_process_id,
       int render_frame_id,
       const content::URLDataSource::GotDataCallback& callback) override;
-  virtual std::string GetSource() const override;
-  virtual std::string GetMimeType(
-      const std::string& path_and_query) const override;
-  virtual bool ShouldDenyXFrameOptions() const override;
-  virtual bool ShouldAddContentSecurityPolicy() const override;
+  std::string GetSource() const override;
+  std::string GetMimeType(const std::string& path_and_query) const override;
+  bool ShouldDenyXFrameOptions() const override;
+  bool ShouldAddContentSecurityPolicy() const override;
 
   // Sends unmodified resource bytes.
   void SendResource(