Standardize usage of virtual/override/final in sync/

sync/test/accounts_client/test_accounts_client.cc

Index: sync/test/accounts_client/test_accounts_client.cc
diff --git a/sync/test/accounts_client/test_accounts_client.cc b/sync/test/accounts_client/test_accounts_client.cc
index 7a5c1e7f9443e5ad19f986f0856030448e061370..587c45fca1a4386fd23cabd85a95edcebcfdd179 100644
--- a/sync/test/accounts_client/test_accounts_client.cc
+++ b/sync/test/accounts_client/test_accounts_client.cc
@@ -39,7 +39,7 @@ class AccountsRequestDelegate : public net::URLFetcherDelegate {
   AccountsRequestDelegate(base::RunLoop* run_loop) : response_(""),
       success_(false), run_loop_(run_loop) {}
 
-  virtual void OnURLFetchComplete(const net::URLFetcher* source) override {
+  void OnURLFetchComplete(const net::URLFetcher* source) override {
     string url = source->GetURL().spec();
     source->GetResponseAsString(&response_);