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

chrome/browser/chromeos/arc/arc_support_host.cc

Index: chrome/browser/chromeos/arc/arc_support_host.cc
diff --git a/chrome/browser/chromeos/arc/arc_support_host.cc b/chrome/browser/chromeos/arc/arc_support_host.cc
index 5ce98ef288893a8496e196911dd76aeb9bd0462e..e1df3fbaf10fd3764596e8d1e1f8ee2160cf9e9f 100644
--- a/chrome/browser/chromeos/arc/arc_support_host.cc
+++ b/chrome/browser/chromeos/arc/arc_support_host.cc
@@ -140,6 +140,8 @@ std::ostream& operator<<(std::ostream& os, ArcSupportHost::Error error) {
       return os << "SERVER_COMMUNICATION_ERROR";
     case ArcSupportHost::Error::ANDROID_MANAGEMENT_REQUIRED_ERROR:
       return os << "ANDROID_MANAGEMENT_REQUIRED_ERROR";
+    case ArcSupportHost::Error::NETWORK_UNAVAILABLE_ERROR:
+      return os << "NETWORK_UNAVAILABLE_ERROR";
   }
 
   // Some compiler reports an error even if all values of an enum-class are
@@ -289,6 +291,9 @@ void ArcSupportHost::ShowError(Error error, bool should_show_send_feedback) {
     case Error::ANDROID_MANAGEMENT_REQUIRED_ERROR:
       message_id = IDS_ARC_ANDROID_MANAGEMENT_REQUIRED_ERROR;
       break;
+    case Error::NETWORK_UNAVAILABLE_ERROR:
+      message_id = IDS_ARC_NETWORK_UNAVAILABLE_ERROR;
+      break;
   }
   message.SetString(kErrorMessage, l10n_util::GetStringUTF16(message_id));
   message.SetBoolean(kShouldShowSendFeedback, should_show_send_feedback);