Enable strict-virtual-specifiers for iOS builds.

components/signin/ios/browser/profile_oauth2_token_service_ios.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/signin/ios/browser/profile_oauth2_token_service_ios.h"
 
 #include <Foundation/Foundation.h>
 
 #include <set>
 #include <string>
@@ skipping 43 matching lines @@
     case ios::kAuthenticationErrorCategoryUnknownIdentityErrors:
       return GoogleServiceAuthError(GoogleServiceAuthError::USER_NOT_SIGNED_UP);
   }
 }
 
 class SSOAccessTokenFetcher : public OAuth2AccessTokenFetcher {
  public:
   SSOAccessTokenFetcher(OAuth2AccessTokenConsumer* consumer,
                         ios::ProfileOAuth2TokenServiceIOSProvider* provider,
                         const std::string account_id);
-  virtual ~SSOAccessTokenFetcher();
+  ~SSOAccessTokenFetcher() override;
 
-  virtual void Start(const std::string& client_id,
-                     const std::string& client_secret,
-                     const std::vector<std::string>& scopes) override;
+  void Start(const std::string& client_id,
+             const std::string& client_secret,
+             const std::vector<std::string>& scopes) override;
 
-  virtual void CancelRequest() override;
+  void CancelRequest() override;
 
   // Handles an access token response.
   void OnAccessTokenResponse(NSString* token,
                              NSDate* expiration,
                              NSError* error);
 
  private:
   ios::ProfileOAuth2TokenServiceIOSProvider* provider_;  // weak
   std::string account_id_;
   bool request_was_cancelled_;
@@ skipping 264 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(!account_id.empty());
 
   if (accounts_.count(account_id) > 0) {
     CancelRequestsForAccount(account_id);
     ClearCacheForAccount(account_id);
     accounts_.erase(account_id);
     FireRefreshTokenRevoked(account_id);
   }
 }