PLANET-6080 Add fonts in HTML head for campaigns

* Also add display=swap for better loading.

single-campaign.php

@@ -100,6 +100,16 @@ static function ( $page ) {
 $context['custom_styles']   = $custom_styles;
 $context['css_vars']        = PostCampaign::css_vars( $campaign_meta );
 
+if ( $theme_name && 'default' !== $theme_name ) {
+	$context['custom_font_families'] = [
+		'Montserrat:300,400,500,600,700,800',
+		'Kanit:400,500,600,800',
+		'Open+Sans:400,500,600,800',
+		'Anton:400,500,600,800',
+		'Amiko:400,500,600,800',
+	];
+}
+
 // Social footer link overrides.
 $context['social_overrides'] = [];
 

templates/head/google_fonts.twig

@@ -0,0 +1,5 @@
+<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700,900&display=swap&subset=latin-ext"/>
+<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lora:400,400i,700&display=swap&subset=latin-ext"/>
+{% for font_family in custom_font_families %}
+	<link rel="stylesheet" href="https://fonts.googleapis.com/css?family={{ font_family }}&display=swap"/>
+{% endfor %}

templates/html-header.twig

@@ -14,8 +14,7 @@
 	<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
 	<meta name="robots" content="max-snippet:-1, max-image-preview:large, max-video-preview:-1">
 	<link rel="shortcut icon" type="image/ico" href="{{ theme.uri }}/favicon.ico"/>
-	<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700,900&display=swap&subset=latin-ext"/>
-	<link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Lora:400,400i,700&display=swap&subset=latin-ext"/>
+	{% include 'head/google_fonts.twig' %}
 
 	{% if hreflang %}
 		<!-- hreflang metadata -->