ListAccounts will return the Gaia ID as well as the email of the account.

components/signin/core/browser/gaia_cookie_manager_service.h

 // 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.
 
 #ifndef COMPONENTS_SIGNIN_CORE_BROWSER_GAIA_COOKIE_MANAGER_SERVICE_H
 #define COMPONENTS_SIGNIN_CORE_BROWSER_GAIA_COOKIE_MANAGER_SERVICE_H
 
 #include <deque>
 
 #include "base/observer_list.h"
 #include "base/timer/timer.h"
 #include "components/signin/core/browser/signin_client.h"
 #include "google_apis/gaia/gaia_auth_consumer.h"
+#include "google_apis/gaia/gaia_auth_util.h"
 #include "google_apis/gaia/ubertoken_fetcher.h"
 #include "net/base/backoff_entry.h"
 #include "net/url_request/url_fetcher_delegate.h"
 
 class GaiaAuthFetcher;
 class GaiaCookieRequest;
 class GoogleServiceAuthError;
 class OAuth2TokenService;
 
 namespace net {
@@ skipping 50 matching lines @@
         const GoogleServiceAuthError& error) {}
 
     // Called whenever the GaiaCookieManagerService's list of GAIA accounts is
     // updated. The GCMS monitors the APISID cookie and triggers a /ListAccounts
     // call on change. The GCMS will also call ListAccounts upon the first call
     // to ListAccounts(). The GCMS will delay calling ListAccounts if other
     // requests are in queue that would modify the APISID cookie.
     // If the ListAccounts call fails and the GCMS cannot recover, the reason
     // is passed in |error|.
     virtual void OnGaiaAccountsInCookieUpdated(
-        const std::vector<std::pair<std::string, bool> >& accounts,
+        const std::vector<gaia::ListedAccount>& accounts,
         const GoogleServiceAuthError& error) {}
 
    protected:
     virtual ~Observer() {}
   };
 
   // Class to retrieve the external connection check results from gaia.
   // Declared publicly for unit tests.
   class ExternalCcResultFetcher : public GaiaAuthConsumer,
                                   public net::URLFetcherDelegate {
@@ skipping 64 matching lines @@
   void Shutdown() override;
 
   void AddAccountToCookie(const std::string& account_id);
   void AddAccountToCookieWithToken(const std::string& account_id,
                                    const std::string& access_token);
 
   // Returns if the listed accounts are up to date or not (ignore the out
   // parameter if return is false). The parameter will be assigned the current
   // cached accounts. If the accounts are not up to date, a ListAccounts fetch
   // is sent GAIA and Observer::OnGaiaAccountsInCookieUpdated will be called.
-  bool ListAccounts(std::vector<std::pair<std::string,bool> >* accounts);
+  bool ListAccounts(std::vector<gaia::ListedAccount>* accounts);
 
   // Add or remove observers of this helper.
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   // Cancel all login requests.
   void CancelAll();
 
   // Signout all accounts.
   void LogOutAllAccounts();
@@ skipping 88 matching lines @@
   // List of observers to notify when merge session completes.
   // Makes sure list is empty on destruction.
   base::ObserverList<Observer, true> observer_list_;
 
   // Source to use with GAIA endpoints for accounting.
   std::string source_;
 
   // True once the ExternalCCResultFetcher has completed once.
   bool external_cc_result_fetched_;
 
-  std::vector<std::pair<std::string, bool> > listed_accounts_;
+  std::vector<gaia::ListedAccount> listed_accounts_;
 
   bool list_accounts_fetched_once_;
 
   DISALLOW_COPY_AND_ASSIGN(GaiaCookieManagerService);
 };
 
 #endif  // COMPONENTS_SIGNIN_CORE_BROWSER_GAIA_COOKIE_MANAGER_SERVICE_H