[a11y] Set focus on "Pairing device" text once QR code is scanned.

Bug: 152462657

Test: Manual. Enable TalkBack in Settings > Accessibility. Navigate to
Developer options > Wireless debugging > Pairing device with QR code.
Scan a valid QR code, which should change to "Pairing device..." and
screen reader should say "Pairing device".

Change-Id: If467b56f787bda765fce1e5d46f8ab3c6210dc76
(cherry picked from commit 07ad841e2d)
Exempt-From-Owner-Approval: cherry-pick

src/com/android/settings/development/AdbQrcodeScannerFragment.java

@@ -73,6 +73,7 @@ public class AdbQrcodeScannerFragment extends WifiDppQrCodeBaseFragment implemen
     private QrDecorateView mDecorateView;
     private View mQrCameraView;
     private View mVerifyingView;
+    private TextView mVerifyingTextView;
     private TextView mErrorMessage;
 
     /** QR code data scanned by camera */
@@ -168,6 +169,7 @@ public class AdbQrcodeScannerFragment extends WifiDppQrCodeBaseFragment implemen
 
         mQrCameraView = view.findViewById(R.id.camera_layout);
         mVerifyingView = view.findViewById(R.id.verifying_layout);
+        mVerifyingTextView = view.findViewById(R.id.verifying_textview);
 
         setHeaderTitle(R.string.wifi_dpp_scan_qr_code);
         mSummary.setText(R.string.adb_wireless_qrcode_pairing_description);
@@ -264,6 +266,8 @@ public class AdbQrcodeScannerFragment extends WifiDppQrCodeBaseFragment implemen
         mDecorateView.setFocused(true);
         mQrCameraView.setVisibility(View.GONE);
         mVerifyingView.setVisibility(View.VISIBLE);
+        AdbQrCode.triggerVibrationForQrCodeRecognition(getContext());
+        mVerifyingTextView.sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_FOCUSED);
         try {
             mAdbManager.enablePairingByQrCode(mAdbConfig.getSsid(),
                     mAdbConfig.getPreSharedKey());