Add refresh_access_token & set_access_token_from_hash methods.

Author: mrj

lib/omniauth/strategies/oauth2.rb

@@ -89,7 +89,7 @@ def callback_phase # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexi
           fail!(error, CallbackError.new(request.params["error"], request.params["error_description"] || request.params["error_reason"], request.params["error_uri"]))
         else
           self.access_token = build_access_token
-          self.access_token = access_token.refresh! if access_token.expired?
+          refresh_access_token if access_token.expired?
           super
         end
       rescue ::OAuth2::Error, CallbackError => e
@@ -100,6 +100,14 @@ def callback_phase # rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexi
         fail!(:failed_to_connect, e)
       end
 
+      def set_access_token_from_hash(hash)
+        self.access_token = ::OAuth2::AccessToken.from_hash(client, hash)
+      end
+
+      def refresh_access_token
+        self.access_token = access_token&.refresh(token_params.to_hash(symbolize_keys: true), deep_symbolize(options.auth_token_params))
+      end
+
     protected
 
       def pkce_authorize_params