Standardize usage of virtual/override/final in chrome/browser/extensions/

chrome/browser/extensions/blacklist_state_fetcher.cc

Index: chrome/browser/extensions/blacklist_state_fetcher.cc
diff --git a/chrome/browser/extensions/blacklist_state_fetcher.cc b/chrome/browser/extensions/blacklist_state_fetcher.cc
index df14b4a7312e1e74a30188a5f3d682c7c32af9ff..3af0bc5b7539d7c4071910f44d1c17e0471ef524 100644
--- a/chrome/browser/extensions/blacklist_state_fetcher.cc
+++ b/chrome/browser/extensions/blacklist_state_fetcher.cc
@@ -46,18 +46,18 @@ class BlacklistRequestContextGetter : public net::URLRequestContextGetter {
                             base::Bind(callback, context_getter));
   }
 
-  virtual net::URLRequestContext* GetURLRequestContext() override {
+  net::URLRequestContext* GetURLRequestContext() override {
     DCHECK_CURRENTLY_ON(BrowserThread::IO);
     return url_request_context_.get();
   }
 
-  virtual scoped_refptr<base::SingleThreadTaskRunner> GetNetworkTaskRunner()
+  scoped_refptr<base::SingleThreadTaskRunner> GetNetworkTaskRunner()
       const override {
     return network_task_runner_;
   }
 
  protected:
-  virtual ~BlacklistRequestContextGetter() {
+  ~BlacklistRequestContextGetter() override {
     url_request_context_->AssertNoURLRequests();
   }