Prefer to use the AccountID to the Email from ListAccounts.

components/signin/core/browser/gaia_cookie_manager_service.cc

 // 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/core/browser/gaia_cookie_manager_service.h"
 
 #include <queue>
 #include <vector>
 
 #include "base/json/json_reader.h"
@@ skipping 543 matching lines @@
          GaiaCookieRequestType::LIST_ACCOUNTS);
   fetcher_backoff_.InformOfRequest(true);
 
   if (!gaia::ParseListAccountsData(data, &listed_accounts_)) {
     listed_accounts_.clear();
     OnListAccountsFailure(GoogleServiceAuthError(
         GoogleServiceAuthError::UNEXPECTED_SERVICE_RESPONSE));
     return;
   }
 
-  for (gaia::ListedAccount account : listed_accounts_) {
+  for (gaia::ListedAccount& account : listed_accounts_) {
+    DCHECK(account.id.empty());
     account.id = AccountTrackerService::PickAccountIdForAccount(
         signin_client_->GetPrefs(), account.gaia_id, account.email);
   }
 
   list_accounts_fetched_once_ = true;
   HandleNextRequest();
   // HandleNextRequest before sending out the notification because some
   // services, in response to OnGaiaAccountsInCookieUpdated, may try in return
   // to call ListAccounts, which would immediately return false if the
   // ListAccounts request is still sitting in queue.
@@ skipping 129 matching lines @@
         break;
       case GaiaCookieRequestType::LIST_ACCOUNTS:
         uber_token_fetcher_.reset();
         signin_client_->DelayNetworkCall(
             base::Bind(&GaiaCookieManagerService::StartFetchingListAccounts,
                        base::Unretained(this)));
         break;
     };
   }
 }