Fix Kerberos accounts changes notification

Kerberos credentials manager should notify observers if at least one of the
account addition succeed. Howerver, there should be at most one notification
for a given list of accounts added. This CL adds a flag to manage this
notifications.

Change-Id: I6f40ed930dd98e9f760a9de9869452d94cec4295
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1871881
Commit-Queue: Felipe Andrade <fsandrade@chromium.org>
Reviewed-by: Lutz Justen <ljusten@chromium.org>
Cr-Commit-Position: refs/heads/master@{#708203}

chrome/browser/chromeos/kerberos/kerberos_credentials_manager.cc

@@ -468,10 +468,15 @@ void KerberosCredentialsManager::OnAddAccountRunnerDone(
     else if (GetActivePrincipalName() == updated_principal)
       GetKerberosFiles();
 
-    // Bring the merry news to the observers, but only if there is no
-    // outstanding query, so we don't spam observers.
-    if (add_account_runners_.empty())
-      NotifyAccountsChanged();
+    // Observers should be notified if at least one of the additions succeed.
+    should_notify_accounts_changes_ = true;
+  }
+
+  // Bring the merry news to the observers, but only if there is no outstanding
+  // query, so we don't spam observers.
+  if (add_account_runners_.empty() && should_notify_accounts_changes_) {
+    should_notify_accounts_changes_ = false;
+    NotifyAccountsChanged();
   }
 
   std::move(callback).Run(error);

chrome/browser/chromeos/kerberos/kerberos_credentials_manager.h

@@ -257,6 +257,9 @@ class KerberosCredentialsManager : public policy::PolicyService::Observer {
   // Keeps track of accounts currently being added.
   std::vector<std::unique_ptr<KerberosAddAccountRunner>> add_account_runners_;
 
+  // Will be true if one of the current account additions succeed.
+  bool should_notify_accounts_changes_ = false;
+
   // Variable expander for the principal name (replaces ${LOGIN_ID} etc.).
   std::unique_ptr<VariableExpander> principal_expander_;