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

components/signin/core/browser/account_reconcilor.cc

Index: components/signin/core/browser/account_reconcilor.cc
diff --git a/components/signin/core/browser/account_reconcilor.cc b/components/signin/core/browser/account_reconcilor.cc
index d7d37145b00383294d2f7f343b6c4fbf942986e9..c93dbf2c754e32cf9949edbc8dd28411be20fdce 100644
--- a/components/signin/core/browser/account_reconcilor.cc
+++ b/components/signin/core/browser/account_reconcilor.cc
@@ -23,16 +23,16 @@
 
 namespace {
 
-class EmailEqualToFunc : public std::equal_to<std::pair<std::string, bool> > {
+class EmailEqualToFunc : public std::equal_to<gaia::ListedAccount> {
  public:
-  bool operator()(const std::pair<std::string, bool>& p1,
-                  const std::pair<std::string, bool>& p2) const;
+  bool operator()(const gaia::ListedAccount& p1,
+                  const gaia::ListedAccount& p2) const;
 };
 
 bool EmailEqualToFunc::operator()(
-    const std::pair<std::string, bool>& p1,
-    const std::pair<std::string, bool>& p2) const {
-  return p1.second == p2.second && gaia::AreEmailsSame(p1.first, p2.first);
+    const gaia::ListedAccount& p1,
+    const gaia::ListedAccount& p2) const {
+  return p1.valid == p2.valid && gaia::AreEmailsSame(p1.email, p2.email);

[Roger Tawa OOO till Jul 10th, 2015/06/02 21:58:41]

Instead of:

   gaia::AreEmailsSame(p1.email, p2.email)

shouldn't this be:

   p1.account_id == p2.account_id

Same for line 47 below.  Doing it this way means the code will work whether we
use gaiaid or email as the account id, and that after we switch to gaiaids, we
will not look at the email at all.

 }
 
 class AreEmailsSameFunc : public std::equal_to<std::string> {
@@ -47,6 +47,14 @@ bool AreEmailsSameFunc::operator()(
   return gaia::AreEmailsSame(p1, p2);
 }
 
+gaia::ListedAccount AccountFromEmail(const std::string& email) {
+  gaia::ListedAccount account;
+  account.email = email;
+  account.gaia_id = std::string();
+  account.valid = true;
+  return account;
+}

[Roger Tawa OOO till Jul 10th, 2015/06/02 21:58:41]

You probably want a function called AccountFromAccountId() which does pretty
much the same thing except with the account_id.

About renaming, probably want to rename the two classes above:

EmailEqualToFunc --> AccountEqualToFunc
AreEmailsSameFunc --> AreAccountsSameFunc

+
 }  // namespace
 
 
@@ -282,7 +290,7 @@ void AccountReconcilor::StartReconcile() {
 }
 
 void AccountReconcilor::OnGaiaAccountsInCookieUpdated(
-        const std::vector<std::pair<std::string, bool> >& accounts,
+        const std::vector<gaia::ListedAccount>& accounts,
         const GoogleServiceAuthError& error) {
   VLOG(1) << "AccountReconcilor::OnGaiaAccountsInCookieUpdated: "
           << "CookieJar " << accounts.size() << " accounts, "
@@ -332,15 +340,15 @@ void AccountReconcilor::FinishReconcile() {
   DCHECK(add_to_cookie_.empty());
   int number_gaia_accounts = gaia_accounts_.size();
   bool are_primaries_equal = number_gaia_accounts > 0 &&
-      gaia::AreEmailsSame(primary_account_, gaia_accounts_[0].first);
+      gaia::AreEmailsSame(primary_account_, gaia_accounts_[0].email);

[Roger Tawa OOO till Jul 10th, 2015/06/02 21:58:41]

This should be:

   primary_account_id_ == gaia_accounts_[0].account_id

 
   // If there are any accounts in the gaia cookie but not in chrome, then
   // those accounts need to be removed from the cookie.  This means we need
   // to blow the cookie away.
   int removed_from_cookie = 0;
   for (size_t i = 0; i < gaia_accounts_.size(); ++i) {
-    const std::string& gaia_account = gaia_accounts_[i].first;
-    if (gaia_accounts_[i].second &&
+    const std::string& gaia_account = gaia_accounts_[i].email;
+    if (gaia_accounts_[i].valid &&
         chrome_accounts_.end() ==
             std::find_if(chrome_accounts_.begin(),
                          chrome_accounts_.end(),
@@ -350,7 +358,7 @@ void AccountReconcilor::FinishReconcile() {
   }
 
   bool rebuild_cookie = !are_primaries_equal || removed_from_cookie > 0;
-  std::vector<std::pair<std::string, bool> > original_gaia_accounts =
+  std::vector<gaia::ListedAccount> original_gaia_accounts =
       gaia_accounts_;
   if (rebuild_cookie) {
     VLOG(1) << "AccountReconcilor::FinishReconcile: rebuild cookie";
@@ -381,8 +389,8 @@ void AccountReconcilor::FinishReconcile() {
             std::find_if(gaia_accounts_.begin(),
                          gaia_accounts_.end(),
                          std::bind1st(EmailEqualToFunc(),
-                                      std::make_pair(add_to_cookie_copy[i],
-                                                     true)))) {
+                                      AccountFromEmail(add_to_cookie_copy[i]
+                                                       )))) {
       cookie_manager_service_->SignalComplete(
           add_to_cookie_copy[i],
           GoogleServiceAuthError::AuthErrorNone());
@@ -392,8 +400,8 @@ void AccountReconcilor::FinishReconcile() {
               std::find_if(original_gaia_accounts.begin(),
                            original_gaia_accounts.end(),
                            std::bind1st(EmailEqualToFunc(),
-                                        std::make_pair(add_to_cookie_copy[i],
-                                                       true)))) {
+                                        AccountFromEmail(add_to_cookie_copy[i]
+                                                         )))) {
         added_to_cookie++;
       }
     }