1) Add initialization error page; 2) Add connection error page.

chrome/browser/chromeos/login/screens/host_pairing_screen.cc

Index: chrome/browser/chromeos/login/screens/host_pairing_screen.cc
diff --git a/chrome/browser/chromeos/login/screens/host_pairing_screen.cc b/chrome/browser/chromeos/login/screens/host_pairing_screen.cc
index 021ab6f5dbbf6028c0e01ea3f11b8cb4361d2c91..6597f09668e16d8f6530de06d130b3418190f81a 100644
--- a/chrome/browser/chromeos/login/screens/host_pairing_screen.cc
+++ b/chrome/browser/chromeos/login/screens/host_pairing_screen.cc
@@ -68,6 +68,10 @@ std::string HostPairingScreen::GetName() const {
 void HostPairingScreen::PairingStageChanged(Stage new_stage) {
   std::string desired_page;
   switch (new_stage) {
+    case HostPairingController::STAGE_INITIALIZATION_ERROR: {
+      desired_page = kPageIntializationError;
+      break;
+    }
     case HostPairingController::STAGE_WAITING_FOR_CONTROLLER:
     case HostPairingController::STAGE_WAITING_FOR_CONTROLLER_AFTER_UPDATE: {
       desired_page = kPageWelcome;
@@ -79,6 +83,10 @@ void HostPairingScreen::PairingStageChanged(Stage new_stage) {
                          remora_controller_->GetConfirmationCode());
       break;
     }
+    case HostPairingController::STAGE_CONTROLLER_CONNECTION_ERROR: {
+      desired_page = kPageConnectionError;
+      break;
+    }
     case HostPairingController::STAGE_SETUP_BASIC_CONFIGURATION: {
       desired_page = kPageSetupBasicConfiguration;
       break;