activatePage( page ) {

		if( !page.active ) {

			page.active = true;

			const { slideElement, backgroundElement, contentElement, indexh, indexv } = page;

			contentElement.style.display = 'block';

			slideElement.classList.add( 'present' );

			if( backgroundElement ) {
				backgroundElement.classList.add( 'present' );
			}

			this.Reveal.setCurrentScrollPage( slideElement, indexh, indexv );
			this.Reveal.backgrounds.bubbleSlideContrastClassToElement( slideElement, this.viewportElement );

			// If this page is part of an auto-animation there will be one
			// content element per auto-animated page. We need to show the
			// current page and hide all others.
			Array.from( contentElement.parentNode.querySelectorAll( '.scroll-page-content' ) ).forEach( sibling => {
				if( sibling !== contentElement ) {
					sibling.style.display = 'none';
				}
			});

		}

	}
Activates the given page and starts its embedded content
if there is any.

@param {object} page