Dismiss SSSS migration toast once migration done

src/DeviceListener.js

@@ -50,6 +50,7 @@ export default class DeviceListener {
         MatrixClientPeg.get().on('crypto.devicesUpdated', this._onDevicesUpdated);
         MatrixClientPeg.get().on('deviceVerificationChanged', this._onDeviceVerificationChanged);
         MatrixClientPeg.get().on('userTrustStatusChanged', this._onUserTrustStatusChanged);
+        MatrixClientPeg.get().on('accountData', this._onAccountData);
         this._recheck();
     }
 
@@ -58,6 +59,7 @@ export default class DeviceListener {
             MatrixClientPeg.get().removeListener('crypto.devicesUpdated', this._onDevicesUpdated);
             MatrixClientPeg.get().removeListener('deviceVerificationChanged', this._onDeviceVerificationChanged);
             MatrixClientPeg.get().removeListener('userTrustStatusChanged', this._onUserTrustStatusChanged);
+            MatrixClientPeg.get().removeListener('accountData', this._onAccountData);
         }
         this._dismissed.clear();
     }
@@ -87,6 +89,13 @@ export default class DeviceListener {
         this._recheck();
     }
 
+    _onAccountData = (ev) => {
+        // User may have migrated SSSS to symmetric, in which case we can dismiss that toast
+        if (ev.getType().startsWith('m.secret_storage.key.')) {
+            this._recheck();
+        }
+    }
+
     // The server doesn't tell us when key backup is set up, so we poll
     // & cache the result
     async _getKeyBackupInfo() {