Removed unused methods from |AccountInfoFetcher|.

Change-Id: I58e1f4983a6bc5480eeae61e63798ede64919324
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1826880Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Matthias Körber <koerber@google.com>
Cr-Commit-Position: refs/heads/master@{#700197}

components/signin/internal/identity_manager/account_info_fetcher.h

@@ -33,8 +33,6 @@ class AccountInfoFetcher : public OAuth2AccessTokenManager::Consumer,
       const CoreAccountId& account_id);
   ~AccountInfoFetcher() override;
 
-  const CoreAccountId& account_id() { return account_id_; }
-
   // Start fetching the account information.
   void Start();