arc: Provide more logging for network failures.

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 4e4ec241d8ecce91df78072dc59b1317ab96673c..299d131e8a5310f14d56ac6b6dee7c0e2163036d 100644
--- a/chrome/browser/chromeos/arc/arc_session_manager.cc
+++ b/chrome/browser/chromeos/arc/arc_session_manager.cc
@@ -344,6 +344,10 @@ void ArcSessionManager::OnProvisioningFinished(ProvisioningResult result) {
     case ProvisioningResult::CHROME_SERVER_COMMUNICATION_ERROR:
       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;
+      break;
     default:
       error = ArcSupportHost::Error::SIGN_IN_UNKNOWN_ERROR;
       break;