Theme_Upgrader::install( string $package, array $args = array() )

	public function install( $package, $args = array() ) {

		$defaults = array(
			'clear_update_cache' => true,
		);
		$parsed_args = wp_parse_args( $args, $defaults );

		$this->init();
		$this->install_strings();

		add_filter('upgrader_source_selection', array($this, 'check_package') );
		add_filter('upgrader_post_install', array($this, 'check_parent_theme_filter'), 10, 3);
		if ( $parsed_args['clear_update_cache'] ) {
			// Clear cache so wp_update_themes() knows about the new theme.
			add_action( 'upgrader_process_complete', 'wp_clean_themes_cache', 9, 0 );
		}

		$this->run( array(
			'package' => $package,
			'destination' => get_theme_root(),
			'clear_destination' => false, //Do not overwrite files.
			'clear_working' => true,
			'hook_extra' => array(
				'type' => 'theme',
				'action' => 'install',
			),
		) );

		remove_action( 'upgrader_process_complete', 'wp_clean_themes_cache', 9 );
		remove_filter('upgrader_source_selection', array($this, 'check_package') );
		remove_filter('upgrader_post_install', array($this, 'check_parent_theme_filter'));

		if ( ! $this->result || is_wp_error($this->result) )
			return $this->result;

		// Refresh the Theme Update information
		wp_clean_themes_cache( $parsed_args['clear_update_cache'] );

		return true;
	}