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

google_apis/gaia/gaia_auth_util.cc

Index: google_apis/gaia/gaia_auth_util.cc
diff --git a/google_apis/gaia/gaia_auth_util.cc b/google_apis/gaia/gaia_auth_util.cc
index 3a9ccab63db6c34604261e8f2538a6fbcb5c719a..33be5a803c1ebf35f43531cd4dab601c74899f9a 100644
--- a/google_apis/gaia/gaia_auth_util.cc
+++ b/google_apis/gaia/gaia_auth_util.cc
@@ -43,6 +43,18 @@ std::string CanonicalizeEmailImpl(const std::string& email_address,
 
 }  // namespace
 
+
+ListedAccount::ListedAccount() {}
+
+ListedAccount::~ListedAccount() {}
+
+bool ListedAccount::operator==(const ListedAccount& other) const {
+  return email == other.email &&
+         gaia_id == other.gaia_id &&
+         valid == other.valid &&
+         raw_email == other.raw_email;

[Roger Tawa OOO till Jul 10th, 2015/06/02 21:58:42]

Do we need to check all fields?  Should be enough to check only account_id.

+}
+
 std::string CanonicalizeEmail(const std::string& email_address) {
   // CanonicalizeEmail() is called to process email strings that are eventually
   // shown to the user, and may also be used in persisting email strings.  To
@@ -94,8 +106,7 @@ bool IsGaiaSignonRealm(const GURL& url) {
 
 
 bool ParseListAccountsData(
-    const std::string& data,
-    std::vector<std::pair<std::string, bool> >* accounts) {
+    const std::string& data, std::vector<ListedAccount>* accounts) {
   accounts->clear();
 
   // Parse returned data and make sure we have data.
@@ -128,8 +139,16 @@ bool ParseListAccountsData(
         if (!account->GetInteger(9, &is_email_valid))
           is_email_valid = 1;
 
-        accounts->push_back(
-            std::make_pair(CanonicalizeEmail(email), is_email_valid != 0));
+        std::string gaia_id;
+        // ListAccounts must also return the Gaia Id.
+        if (account->GetString(10, &gaia_id) && !gaia_id.empty()) {
+          ListedAccount listed_account;
+          listed_account.email = CanonicalizeEmail(email);
+          listed_account.gaia_id = gaia_id;
+          listed_account.valid = is_email_valid != 0;
+          listed_account.raw_email = email;
+          accounts->push_back(listed_account);
+        }
       }
     }
   }