GCMS has automatic checks for CheckExternalConnections. It will be

components/signin/core/browser/gaia_cookie_manager_service.cc

Index: components/signin/core/browser/gaia_cookie_manager_service.cc
diff --git a/components/signin/core/browser/gaia_cookie_manager_service.cc b/components/signin/core/browser/gaia_cookie_manager_service.cc
index 36ba75a96fa725b20ce0d281a7c88f1872f328e0..a25374d51aa704f0c630c457ddae5dbf93dcfb7c 100644
--- a/components/signin/core/browser/gaia_cookie_manager_service.cc
+++ b/components/signin/core/browser/gaia_cookie_manager_service.cc
@@ -265,8 +265,13 @@ void GaiaCookieManagerService::ExternalCcResultFetcher::
       base::Time::Now() - m_external_cc_result_start_time_;
   signin_metrics::LogExternalCcResultFetches(succeeded,
                                              time_to_check_connections);
-  FOR_EACH_OBSERVER(Observer, helper_->observer_list_,
-                    GetCheckConnectionInfoCompleted(succeeded));
+
+  helper_->external_cc_result_fetched_ = true;
+  // Since the ExternalCCResultFetcher is only Started in place of calling
+  // StartFetchingMergeSession, we can assume we need to call
+  // StartFetchingMergeSession. If this assumption becomes invalid, a Callback
+  // will need to be passed to Start() and Run() here.
+  helper_->StartFetchingMergeSession();
 }
 
 GaiaCookieManagerService::GaiaCookieManagerService(
@@ -278,7 +283,8 @@ GaiaCookieManagerService::GaiaCookieManagerService(
       external_cc_result_fetcher_(this),
       gaia_auth_fetcher_backoff_(&kBackoffPolicy),
       gaia_auth_fetcher_retries_(0),
-      source_(source) {
+      source_(source),
+      external_cc_result_fetched_(false) {
 }
 
 GaiaCookieManagerService::~GaiaCookieManagerService() {
@@ -387,11 +393,6 @@ void GaiaCookieManagerService::SignalComplete(
                     OnAddAccountToCookieCompleted(account_id, error));
 }
 
-void GaiaCookieManagerService::StartFetchingExternalCcResult() {
-  if (!external_cc_result_fetcher_.IsRunning())
-    external_cc_result_fetcher_.Start();
-}
-
 void GaiaCookieManagerService::StartLogOutUrlFetch() {
   DCHECK(requests_.front().request_type() == GaiaCookieRequestType::LOG_OUT);
   VLOG(1) << "GaiaCookieManagerService::StartLogOutUrlFetch";
@@ -405,10 +406,19 @@ void GaiaCookieManagerService::StartLogOutUrlFetch() {
 
 void GaiaCookieManagerService::OnUbertokenSuccess(
     const std::string& uber_token) {
+  DCHECK(requests_.front().request_type() ==
+      GaiaCookieRequestType::ADD_ACCOUNT);
   VLOG(1) << "GaiaCookieManagerService::OnUbertokenSuccess"
           << " account=" << requests_.front().account_id();
   gaia_auth_fetcher_retries_ = 0;
   uber_token_ = uber_token;
+
+  if (!external_cc_result_fetched_ &&
+      !external_cc_result_fetcher_.IsRunning()) {
+    external_cc_result_fetcher_.Start();
+    return;
+  }
+
   StartFetchingMergeSession();
 }
 
@@ -469,8 +479,6 @@ void GaiaCookieManagerService::StartFetchingMergeSession() {
       new GaiaAuthFetcher(this, source_,
                           signin_client_->GetURLRequestContext()));
 
-  // It's possible that not all external checks have completed.
-  // GetExternalCcResult() returns results for those that have.
   gaia_auth_fetcher_->StartMergeSession(uber_token_,
       external_cc_result_fetcher_.GetExternalCcResult());
 }