Twenty Fifteen: Improve site description handling within the Customizer.

[philiparthurmoore]

Right now, this is the code that’s used to output site descriptions in Twenty Fifteen:

<?php
					$description = get_bloginfo( 'description', 'display' );
					if ( ! empty( $description ) ) : ?>
						<p class="site-description"><?php echo esc_html( $description ); ?></p>
					<?php endif;

That’s nice because junky markup isn’t added into the front-end when a blog description is empty. This is problematic, though, inside of the Customizer when using postMessage.

1. Make your site description blank.
2. Reload your Customizer.
3. Try to add a description into the site.
4. Nothing is reflected inside of the customizer.

Because no markup is present for postMessage when a site description is empty we either need to a) revert get_setting( 'blogdescription' )->transport to refresh by removing that line altogether (since refresh is the default) or b) add some logic into header.php that outputs markup when we’re inside of the customizer and a site title is empty.

[celloexpressions]

Let's do the second option - just change the conditional to if ( ! empty( $description ) || is_customize_preview() ) and we should be good to go.

[philiparthurmoore]

Cool. Patch incoming.

[iandstewart]

In 30391:

Twenty Fifteen: Check if we're in the customizer before we avoid outputting HTML for an empty tagline. Avoids an issue with a not-updating customizer preview of the tagline if you're going in with an empty tagline.

Props philiparthurmoore, celloexpressions, fixes #30358.