Remove MutableProfileOAuth2TokenService on iOS.

components/signin/core/browser/mutable_profile_oauth2_token_service.cc

Index: components/signin/core/browser/mutable_profile_oauth2_token_service.cc
diff --git a/components/signin/core/browser/mutable_profile_oauth2_token_service.cc b/components/signin/core/browser/mutable_profile_oauth2_token_service.cc
index d62a30d9041f149761c4272cdfc481562a5a6473..a9e4442911008541480af2cf26eaabcb3ca43aa2 100644
--- a/components/signin/core/browser/mutable_profile_oauth2_token_service.cc
+++ b/components/signin/core/browser/mutable_profile_oauth2_token_service.cc
@@ -270,16 +270,6 @@ void MutableProfileOAuth2TokenService::UpdateAuthError(
       error.state() == GoogleServiceAuthError::SERVICE_UNAVAILABLE)
     return;
 
-#if defined(OS_IOS)
-  // ProfileOauth2TokenService does not manage the refresh tokens on iOS - the
-  // account info on iOS is only used to manage the authentication error state.
-  // Simply add an account info entry with empty refresh token if none exists.
-  if (refresh_tokens_.count(account_id) == 0) {
-      refresh_tokens_[account_id].reset(
-          new AccountInfo(this, account_id, std::string()));
-  }
-#endif
-
   if (refresh_tokens_.count(account_id) == 0) {
     // This could happen if the preferences have been corrupted (see
     // http://crbug.com/321370). In a Debug build that would be a bug, but in a