Use data-hero-candidate attribute in DetermineHeroImages

composer.json

@@ -13,7 +13,7 @@
     "ext-json": "*",
     "ext-libxml": "*",
     "ext-spl": "*",
-    "ampproject/amp-toolbox": "^0.1",
+    "ampproject/amp-toolbox": "^0.2",
     "cweagans/composer-patches": "1.7.0",
     "fasterimage/fasterimage": "1.5.0",
     "sabberworm/php-css-parser": "dev-master#bfdd976"

includes/class-amp-theme-support.php

@@ -6,6 +6,7 @@
  */
 
 use AmpProject\Amp;
+use AmpProject\AmpWP\Dom\Options;
 use AmpProject\AmpWP\ExtraThemeAndPluginHeaders;
 use AmpProject\AmpWP\Option;
 use AmpProject\AmpWP\QueryVar;
@@ -1867,7 +1868,7 @@ public static function prepare_response( $response, $args = [] ) {
 		 */
 		do_action( 'amp_server_timing_start', 'amp_dom_parse', '', [], true );
 
-		$dom = Document::fromHtml( $response );
+		$dom = Document::fromHtml( $response, Options::DEFAULTS );
 
 		if ( AMP_Validation_Manager::$is_validate_request ) {
 			AMP_Validation_Manager::remove_illegal_source_stack_comments( $dom );
@@ -2117,8 +2118,6 @@ private static function get_optimizer_configuration( $args ) {
 					Optimizer\Transformer\TransformedIdentifier::class,
 				]
 			);
-		} else {
-			array_unshift( $transformers, Transformer\DetermineHeroImages::class );
 		}
 
 		array_unshift( $transformers, Transformer\AmpSchemaOrgMetadata::class );

includes/sanitizers/class-amp-core-theme-sanitizer.php

@@ -6,8 +6,10 @@
  * @since 1.0
  */
 
+use AmpProject\AmpWP\Transformer\DetermineHeroImages;
 use AmpProject\Attribute;
 use AmpProject\Dom\Document;
+use AmpProject\Optimizer\Configuration;
 use AmpProject\Role;
 
 /**
@@ -99,6 +101,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 					'amend_twentytwentyone_sub_menu_toggles' => [],
 					'add_twentytwentyone_mobile_modal' => [],
 					'add_twentytwentyone_sub_menu_fix' => [],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 				// Dark mode button toggle is only supported in the Customizer for now.
@@ -139,6 +142,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 					'add_img_display_block_fix'        => [],
 					'add_twentytwenty_custom_logo_fix' => [],
 					'add_twentytwenty_current_page_awareness' => [],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 				$theme = wp_get_theme( 'twentytwenty' );
@@ -166,6 +170,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 					],
 					'add_twentynineteen_masthead_styles' => [],
 					'adjust_twentynineteen_images'       => [],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Seventeen.
@@ -201,6 +206,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 					],
 					'set_twentyseventeen_quotes_icon'     => [],
 					'add_twentyseventeen_attachment_image_attributes' => [],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Sixteen.
@@ -223,6 +229,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 						'sub_menu_button_toggle_class' => 'toggled-on',
 						'no_js_submenu_visible'        => true,
 					],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Fifteen.
@@ -243,6 +250,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 						'sub_menu_button_toggle_class' => 'toggle-on',
 						'no_js_submenu_visible'        => true,
 					],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Fourteen.
@@ -259,6 +267,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 					'add_twentyfourteen_masthead_styles' => [],
 					'add_twentyfourteen_slider_carousel' => [],
 					'add_twentyfourteen_search'          => [],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Thirteen.
@@ -271,6 +280,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 					'add_nav_menu_toggle'      => [],
 					'add_nav_sub_menu_buttons' => [],
 					'add_nav_menu_styles'      => [],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Twelve.
@@ -280,6 +290,7 @@ protected static function get_theme_features_config( $theme_slug ) {
 						'twentytwelve-navigation',
 					],
 					'add_nav_menu_styles' => [],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Eleven.
@@ -289,11 +300,14 @@ protected static function get_theme_features_config( $theme_slug ) {
 						'//style[ @id = "twentyeleven-header-css" ]',
 						'//link[ @id = "dark-css" ]',
 					],
+					'enable_determine_hero_images_transformer' => [],
 				];
 
 			// Twenty Ten.
 			case 'twentyten':
-				return [];
+				return [
+					'enable_determine_hero_images_transformer' => [],
+				];
 
 			default:
 				return null;
@@ -533,6 +547,25 @@ public static function add_buffering_hooks( $args = [] ) {
 		}
 	}
 
+	/**
+	 * Enable transformer that identifies hero image candidates for prerendering.
+	 *
+	 * Note that this transformer will likely be enabled by default in the future. It is only enabled by default for
+	 * core themes in the immediate term since it is known to work well with this set of themes.
+	 *
+	 * @since 2.1
+	 */
+	public static function enable_determine_hero_images_transformer() {
+		add_filter(
+			'amp_optimizer_config',
+			static function ( $config ) {
+				array_unshift( $config[ Configuration::KEY_TRANSFORMERS ], DetermineHeroImages::class );
+				return $config;
+			},
+			9
+		);
+	}
+
 	/**
 	 * Add filter to output the quote icons in front of the article content.
 	 *

includes/sanitizers/class-amp-meta-sanitizer.php

@@ -295,7 +295,7 @@ protected function create_charset_element() {
 			$this->dom,
 			Tag::META,
 			[
-				Attribute::CHARSET => Document::AMP_ENCODING,
+				Attribute::CHARSET => Document\Encoding::AMP,
 			]
 		);
 	}

includes/utils/class-amp-dom-utils.php

@@ -5,7 +5,9 @@
  * @package AMP
  */
 
+use AmpProject\AmpWP\Dom\Options;
 use AmpProject\Dom\Document;
+use AmpProject\Dom\Element;
 use AmpProject\Tag;
 
 /**
@@ -65,7 +67,14 @@ class AMP_DOM_Utils {
 	 */
 	public static function get_dom( $document, $encoding = null ) {
 		_deprecated_function( __METHOD__, '1.5.0', 'AmpProject\Dom\Document::fromHtml()' );
-		return Document::fromHtml( $document, $encoding );
+
+		$options = Options::DEFAULTS;
+
+		if ( null !== $encoding ) {
+			$options[ Document\Option::ENCODING ] = $encoding;
+		}
+
+		return Document::fromHtml( $document, $options );
 	}
 
 	/**
@@ -172,7 +181,10 @@ public static function get_dom_from_content( $content, $encoding = null ) {
 		 */
 		$document = "<html><head></head><body>{$content}</body></html>";
 
-		return Document::fromHtml( $document, $encoding );
+		$options                              = Options::DEFAULTS;
+		$options[ Document\Option::ENCODING ] = $encoding;
+
+		return Document::fromHtml( $document, $options );
 	}
 
 	/**
@@ -375,8 +387,8 @@ public static function has_class( DOMElement $element, $class ) {
 	 *
 	 * @deprecated Use AmpProject\Dom\Document::getElementId() instead.
 	 *
-	 * @param DOMElement $element Element to get the ID for.
-	 * @param string     $prefix  Optional. Defaults to 'amp-wp-id'.
+	 * @param DOMElement|Element $element Element to get the ID for.
+	 * @param string             $prefix  Optional. Defaults to 'amp-wp-id'.
 	 * @return string ID to use.
 	 */
 	public static function get_element_id( $element, $prefix = 'amp-wp-id' ) {

src/Dom/Options.php

@@ -0,0 +1,22 @@
+<?php
+/**
+ * Class Options.
+ *
+ * @package AmpProject\AmpWP
+ */
+
+namespace AmpProject\AmpWP\Dom;
+
+use AmpProject\Dom\Document;
+
+interface Options {
+
+	/**
+	 * Default options to use for the Dom.
+	 *
+	 * @var array
+	 */
+	const DEFAULTS = [
+		Document\Option::AMP_BIND_SYNTAX => Document\Option::AMP_BIND_SYNTAX_DATA_ATTRIBUTE,
+	];
+}