Standardize usage of virtual/override/final in components/

components/dom_distiller/content/dom_distiller_viewer_source.h

Index: components/dom_distiller/content/dom_distiller_viewer_source.h
diff --git a/components/dom_distiller/content/dom_distiller_viewer_source.h b/components/dom_distiller/content/dom_distiller_viewer_source.h
index d9eaf9fb7247b0d85017dd1d6eaf5fe112a0e01e..5a9721e0dd13f6e613ec82f3acff684c315f6799 100644
--- a/components/dom_distiller/content/dom_distiller_viewer_source.h
+++ b/components/dom_distiller/content/dom_distiller_viewer_source.h
@@ -23,23 +23,22 @@ class DomDistillerViewerSource : public content::URLDataSource {
  public:
   DomDistillerViewerSource(DomDistillerServiceInterface* dom_distiller_service,
                            const std::string& scheme);
-  virtual ~DomDistillerViewerSource();
+  ~DomDistillerViewerSource() override;
 
   class RequestViewerHandle;
 
   // Overridden from content::URLDataSource:
-  virtual std::string GetSource() const override;
-  virtual void StartDataRequest(
+  std::string GetSource() const override;
+  void StartDataRequest(
       const std::string& path,
       int render_process_id,
       int render_frame_id,
       const content::URLDataSource::GotDataCallback& callback) override;
-  virtual std::string GetMimeType(const std::string& path) const override;
-  virtual bool ShouldServiceRequest(
-      const net::URLRequest* request) const override;
-  virtual void WillServiceRequest(const net::URLRequest* request,
-                                  std::string* path) const override;
-  virtual std::string GetContentSecurityPolicyObjectSrc() const override;
+  std::string GetMimeType(const std::string& path) const override;
+  bool ShouldServiceRequest(const net::URLRequest* request) const override;
+  void WillServiceRequest(const net::URLRequest* request,
+                          std::string* path) const override;
+  std::string GetContentSecurityPolicyObjectSrc() const override;
 
  private:
   friend class DomDistillerViewerSourceTest;