Add support for specifying the screen after require_registration

Also use it in start chat and join group

Signed-off-by: Stuart Mumford <stuart@cadair.com>

src/Registration.js

@@ -39,6 +39,8 @@ export const SAFE_LOCALPART_REGEX = /^[a-z0-9=_\-./]+$/;
  *     If true, goes to the home page if the user cancels the action
  * @param {bool} options.go_welcome_on_cancel
  *     If true, goes to the welcome page if the user cancels the action
+ * @param {bool} options.screen_after
+ *     If present the screen to redict to after a successful login or register.
  */
 export async function startAnyRegistrationFlow(options) {
     if (options === undefined) options = {};
@@ -72,13 +74,15 @@ export async function startAnyRegistrationFlow(options) {
             button: _t("Register"),
             extraButtons: [
                 <button className="mx_Dialog_primary"
-                onClick={() => {modal.close(); dis.dispatch({action: 'start_login'});}}>
+                onClick={() => {modal.close(); dis.dispatch({action: 'start_login',
+                                                             screenAfterLogin: options.screen_after});}}>
                     { _t('Login') }
                 </button>,
             ],
             onFinished: (proceed) => {
                 if (proceed) {
-                    dis.dispatch({action: 'start_registration'});
+                    dis.dispatch({action: 'start_registration',
+                                  screenAfterLogin: options.screen_after});
                 } else if (options.go_home_on_cancel) {
                     dis.dispatch({action: 'view_home_page'});
                 } else if (options.go_welcome_on_cancel) {

src/components/structures/GroupView.js

@@ -481,7 +481,8 @@ export default createReactClass({
                         group_id: groupId,
                     },
                 });
-                dis.dispatch({action: 'require_registration'});
+                dis.dispatch({action: 'require_registration',
+                              screen_after: {screen: `group/${groupId}`}});
                 willDoOnboarding = true;
             }
             if (stateKey === GroupStore.STATE_KEY.Summary) {
@@ -726,7 +727,8 @@ export default createReactClass({
 
     _onJoinClick: async function() {
         if (this._matrixClient.isGuest()) {
-            dis.dispatch({action: 'require_registration'});
+            dis.dispatch({action: 'require_registration',
+                          screen_after: {screen: `group/${this.props.groupId}`}});
             return;
         }
 

src/components/structures/MatrixChat.js

@@ -1008,6 +1008,11 @@ export default createReactClass({
                 // needs to be reset so that they can revisit /user/.. // (and trigger
                 // `_chatCreateOrReuse` again)
                 go_welcome_on_cancel: true,
+                screen_after: {screen: `user/${this.props.config.welcomeUserId}`,
+                               params: {
+                                   action: 'chat'
+                               }
+                              }
             });
             return;
         }