Code review comment for lp:~marcustomlinson/unity-scopes-shell/oa_loading_bar

In the case where either:
   1. A new account is added from settings, the scope service is enabled under that account, then the log-in button is pressed in a scope.
   2. The token for a scope expires (bringing the log-in button back), then the log-in button is pressed in the scope.

The call to OA to refresh the token takes some time to return with no UI indication.

This branch uses setSearchInProgress() in order to animate the scope's loading bar while we wait for the token to be returned.

NOTE: The reason I need to use ExcludeUserInputEvents for the event loop here is because we can't allow the user move to another scope / open a preview while this method is busy. This is because the post log-in action needs to be performed from the state the scope was at the time the log-in button was pressed.