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

components/pairing/bluetooth_host_pairing_controller.cc

Index: components/pairing/bluetooth_host_pairing_controller.cc
diff --git a/components/pairing/bluetooth_host_pairing_controller.cc b/components/pairing/bluetooth_host_pairing_controller.cc
index 37e4854239b87c7a8199820c9ca0c6cf5d01050c..394f27185ed88f2544028d608a30eaf7497e7315 100644
--- a/components/pairing/bluetooth_host_pairing_controller.cc
+++ b/components/pairing/bluetooth_host_pairing_controller.cc
@@ -308,17 +308,20 @@ void BluetoothHostPairingController::OnSetError() {
 void BluetoothHostPairingController::OnAcceptError(
     const std::string& error_message) {
   LOG(ERROR) << error_message;
+  ChangeStage(STAGE_CONTROLLER_CONNECTION_ERROR);
 }
 
 void BluetoothHostPairingController::OnSendError(
     const std::string& error_message) {
   LOG(ERROR) << error_message;
+  ChangeStage(STAGE_CONTROLLER_CONNECTION_ERROR);

[dzhioev (left Google), 2015/12/17 23:33:32]

I don't think we should call this if |enrollment_status_| is
ENROLLMENT_STATUS_ENROLLING or ENROLLMENT_STATUS_SUCCESS.

[xdai1, 2015/12/17 23:49:08]

Agreed. Addressed your comment.

 }
 
 void BluetoothHostPairingController::OnReceiveError(
     device::BluetoothSocket::ErrorReason reason,
     const std::string& error_message) {
   LOG(ERROR) << reason << ", " << error_message;
+  ChangeStage(STAGE_CONTROLLER_CONNECTION_ERROR);
 }
 
 void BluetoothHostPairingController::OnHostStatusMessage(
@@ -352,6 +355,7 @@ void BluetoothHostPairingController::OnCompleteSetupMessage(
     const pairing_api::CompleteSetup& message) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (current_stage_ != STAGE_ENROLLMENT_SUCCESS) {
+    ChangeStage(STAGE_ENROLLMENT_ERROR);
     AbortWithError(PAIRING_ERROR_PAIRING_OR_ENROLLMENT, kErrorInvalidProtocol);
     return;
   }