Standardize usage of virtual/override/final specifiers.

components/dom_distiller/standalone/content_extractor.cc

Index: components/dom_distiller/standalone/content_extractor.cc
diff --git a/components/dom_distiller/standalone/content_extractor.cc b/components/dom_distiller/standalone/content_extractor.cc
index b6a5a4e98995f031a480efbf158ac52d48a2b8c7..8f960b2d03528dda4badd42339f25aa6b22dbd75 100644
--- a/components/dom_distiller/standalone/content_extractor.cc
+++ b/components/dom_distiller/standalone/content_extractor.cc
@@ -209,11 +209,9 @@ class ContentExtractionRequest : public ViewRequestDelegate {
  private:
   ContentExtractionRequest(const GURL& url) : url_(url) {}
 
-  virtual void OnArticleUpdated(ArticleDistillationUpdate article_update)
-      override {}
+  void OnArticleUpdated(ArticleDistillationUpdate article_update) override {}
 
-  virtual void OnArticleReady(const DistilledArticleProto* article_proto)
-      override {
+  void OnArticleReady(const DistilledArticleProto* article_proto) override {
     article_proto_ = article_proto;
     CHECK(article_proto->pages_size()) << "Failed extracting " << url_;
     base::MessageLoop::current()->PostTask(
@@ -239,7 +237,7 @@ class ContentExtractor : public ContentBrowserTest {
 
   // Change behavior of the default host resolver to avoid DNS lookup errors, so
   // we can make network calls.
-  virtual void SetUpOnMainThread() override {
+  void SetUpOnMainThread() override {
     if (!CommandLine::ForCurrentProcess()->HasSwitch(kDisableDnsSwitch)) {
       EnableDNSLookupForThisTest();
     }
@@ -247,9 +245,7 @@ class ContentExtractor : public ContentBrowserTest {
     AddComponentsResources();
   }
 
-  virtual void TearDownOnMainThread() override {
-    DisableDNSLookupForThisTest();
-  }
+  void TearDownOnMainThread() override { DisableDNSLookupForThisTest(); }
 
  protected:
   // Creates the DomDistillerService and creates and starts the extraction