Themes: inconsistent exit behavior exiting the Customizer after changing a theme

[lancewillett]

This issue is a series of related Customizer bugs that happen in Calypso, specifically when exiting the Customizer after changing a theme.

Issue 1:

1/ Go to Calypso single site view, click on 'Customize' button

2/ Change the site theme & the site title:

3/ Click on 'Save & Activate'

Actual result: See the front page of the site
Expected result: To go back to Calypso Themes with a confirmation screen about changing the theme:

The success message would be consistent with the rest of Themes behavior of confirming the theme change.

Issue 2:

1/ Go to Calypso > Themes, click on 'Customize' for the current theme:

2/ Change theme to something else:

3/ Click on 'Save & Activate'

Actual result: Go to the front page of the site
Expected result: Go back to Calypso Themes and see a success message about changing the theme:

Issue 3:

1/ Go to Calypso > Themes, click on 'Customize' for the current theme:

2/ Change the site theme & the site title:

3/ Click on 'Save & Activate'

Actual result: Go to the front page of the site
Expected result: Go back to Calypso Themes and see a success message about changing the theme:

Solution

The best possible outcome here is to redirect back to the Showcase if the Customizer has been accessed via a Showcase link.

Why? Because once the theme has been changed from within the Customizer, we should go back to our welcome message. It's not perfect but at least it gives the user a choice: Back to themes or Visit site.

[mattwiebe]

These instances should all be fixed now that #1227 is closed. Those cases all involved breaking out of Calypso due to the way theme previewing in the Customizer works.