Add BLE pairing begin dialog

Add dialog before BLE device selection view instructing the user to
begin pairing process.

Bug: 877344
Change-Id: I9f8bf8b011231a20a09ebbb2ab8073792df276ef
Reviewed-on: https://chromium-review.googlesource.com/c/1356122
Commit-Queue: Jun Choi <hongjunchoi@chromium.org>
Reviewed-by: Kim Paulhamus <kpaulhamus@chromium.org>
Cr-Commit-Position: refs/heads/master@{#612560}

chrome/browser/ui/webauthn/sheet_models.cc

@@ -438,6 +438,11 @@ base::string16 AuthenticatorBlePairingBeginSheetModel::GetAcceptButtonLabel()
   return l10n_util::GetStringUTF16(IDS_WEBAUTHN_BLE_PAIRING_BEGIN_NEXT);
 }
 
+void AuthenticatorBlePairingBeginSheetModel::OnAccept() {
+  dialog_model()->SetCurrentStep(
+      AuthenticatorRequestDialogModel::Step::kBleDeviceSelection);
+}
+
 // AuthenticatorBleEnterPairingModeSheetModel ---------------------------------
 
 gfx::ImageSkia*

chrome/browser/ui/webauthn/sheet_models.h

@@ -233,6 +233,7 @@ class AuthenticatorBlePairingBeginSheetModel
   bool IsAcceptButtonVisible() const override;
   bool IsAcceptButtonEnabled() const override;
   base::string16 GetAcceptButtonLabel() const override;
+  void OnAccept() override;
 };
 
 class AuthenticatorBleEnterPairingModeSheetModel

chrome/browser/webauthn/authenticator_request_dialog_model.cc

@@ -153,7 +153,7 @@ void AuthenticatorRequestDialogModel::StartGuidedFlowForTransport(
       Step next_step = ShouldShowBlePairingUI(
                            previously_paired_with_bluetooth_authenticator_,
                            pair_with_new_device_for_bluetooth_low_energy)
-                           ? Step::kBleDeviceSelection
+                           ? Step::kBlePairingBegin
                            : Step::kBleActivate;
       EnsureBleAdapterIsPoweredBeforeContinuingWithStep(next_step);
       break;

chrome/browser/webauthn/authenticator_request_dialog_model_unittest.cc

@@ -371,7 +371,7 @@ TEST_F(AuthenticatorRequestDialogModelTest, BlePairingFlow) {
     Step expected_final_step;
   } kTestCases[] = {
       {AuthenticatorTransport::kBluetoothLowEnergy, nullptr,
-       Step::kBleDeviceSelection},
+       Step::kBlePairingBegin},
       {AuthenticatorTransport::kBluetoothLowEnergy, &test_paired_device_list_,
        Step::kBleActivate},
   };