Fix sign-in error strings.

chrome/browser/extensions/api/identity/account_tracker.cc

Index: chrome/browser/extensions/api/identity/account_tracker.cc
diff --git a/chrome/browser/extensions/api/identity/account_tracker.cc b/chrome/browser/extensions/api/identity/account_tracker.cc
index c372a0b27151768584b42dd8b817a21c461de067..95155e3763ac8f024c041d253cec574c8a96ccd8 100644
--- a/chrome/browser/extensions/api/identity/account_tracker.cc
+++ b/chrome/browser/extensions/api/identity/account_tracker.cc
@@ -206,6 +206,16 @@ std::string AccountTracker::GetAccountId() const {
     return account_errors_.begin()->first;
 }
 
+std::string AccountTracker::GetUsername() const {
+  if (account_errors_.size() > 0) {
+    std::map<std::string, AccountState>::const_iterator it =
+        accounts_.find(account_errors_.begin()->first);
+    if (it != accounts_.end())
+      return it->second.ids.email;
+  }
+  return std::string();
+}
+
 GoogleServiceAuthError AccountTracker::GetAuthStatus() const {
   if (account_errors_.size() == 0)
     return GoogleServiceAuthError::AuthErrorNone();