replace OVERRIDE and FINAL with override and final in chrome/browser/extensions/

BUG=417463

Review URL: https://codereview.chromium.org/624153002

Cr-Commit-Position: refs/heads/master@{#298134}
diff --git a/chrome/browser/extensions/favicon_downloader.h b/chrome/browser/extensions/favicon_downloader.h
index 36bf23fa..e9142709 100644
--- a/chrome/browser/extensions/favicon_downloader.h
+++ b/chrome/browser/extensions/favicon_downloader.h
@@ -67,9 +67,9 @@
   // content::WebContentsObserver overrides:
   virtual void DidNavigateMainFrame(
       const content::LoadCommittedDetails& details,
-      const content::FrameNavigateParams& params) OVERRIDE;
+      const content::FrameNavigateParams& params) override;
   virtual void DidUpdateFaviconURL(
-      const std::vector<content::FaviconURL>& candidates) OVERRIDE;
+      const std::vector<content::FaviconURL>& candidates) override;
 
   // Whether we have received favicons from the renderer.
   bool got_favicon_urls_;