arc: Add explicit error message in case network cannot be setup.

chrome/browser/chromeos/arc/arc_session_manager.cc

Index: chrome/browser/chromeos/arc/arc_session_manager.cc
diff --git a/chrome/browser/chromeos/arc/arc_session_manager.cc b/chrome/browser/chromeos/arc/arc_session_manager.cc
index d59ec468961c8e5fd356c513380e9e0f5c9c300e..8a38c01ca6be1597837ae7a97d2a0ade72f898c8 100644
--- a/chrome/browser/chromeos/arc/arc_session_manager.cc
+++ b/chrome/browser/chromeos/arc/arc_session_manager.cc
@@ -295,8 +295,7 @@ void ArcSessionManager::OnProvisioningFinished(ProvisioningResult result) {
       error = ArcSupportHost::Error::SERVER_COMMUNICATION_ERROR;
       break;
     case ProvisioningResult::NO_NETWORK_CONNECTION:
-      // TODO(khmel): Use explicit error for M58+ builds.
-      error = ArcSupportHost::Error::SIGN_IN_SERVICE_UNAVAILABLE_ERROR;
+      error = ArcSupportHost::Error::NETWORK_UNAVAILABLE_ERROR;
       break;
     case ProvisioningResult::ARC_DISABLED:
       error = ArcSupportHost::Error::ANDROID_MANAGEMENT_REQUIRED_ERROR;