Support <picture> in image extraction

java/org/chromium/distiller/extractors/embeds/ImageExtractor.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.distiller.extractors.embeds;
 
 import com.google.gwt.dom.client.Document;
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.ImageElement;
 import com.google.gwt.dom.client.NodeList;
@@ skipping 11 matching lines @@
  */
 public class ImageExtractor implements EmbedExtractor {
     private static final Set<String> relevantTags = new HashSet<>();
     private String imgSrc;
     private int width;
     private int height;
 
     static {
         // TODO(mdjones): Add "DIV" to this list for css images and possibly captions.
         relevantTags.add("IMG");
+        relevantTags.add("PICTURE");
         relevantTags.add("FIGURE");
     }
 
     private static final String[] LAZY_IMAGE_ATTRIBUTES =
             {"data-src", "data-original", "datasrc", "data-url"};
 
     @Override
     public Set<String> getRelevantTagNames() {
         return relevantTags;
     }
 
     @Override
     public WebImage extract(Element e) {
         if (!relevantTags.contains(e.getTagName())) {
             return null;
         }
         imgSrc = "";
 
-        if ("IMG".equals(e.getTagName())) {
-            extractImageAttributes(ImageElement.as(e));
-            return new WebImage(e, width, height, imgSrc);
-        } else if ("FIGURE".equals(e.getTagName())) {
-            Element img = getFirstElementByTagName(e, "IMG");
-            if (img != null) {
-                extractImageAttributes(ImageElement.as(img));
-                Element figcaption;
-                Element cap = getFirstElementByTagName(e, "FIGCAPTION");
-                if (cap != null) {
-                    // We look for links because some sites put non-caption
-                    // elements into <figcaption>. For example: image credit
-                    // could contain a link. So we get the whole DOM structure within
-                    // <figcaption> only when it contains links, otherwise we get the innerText.
-                    figcaption = getFirstElementByTagName(cap, "A") != null ?
-                            cap : createFigcaptionElement(cap);
-                } else {
-                    figcaption = createFigcaptionElement(e);
-                }
-                return new WebFigure(img, width, height, imgSrc, figcaption);
+        ImageElement ie = ImageElement.as(DomUtil.getFirstElementByTagNameInc(e, "IMG"));
+
+        if ("FIGURE".equals(e.getTagName())) {
+            Element img = DomUtil.getFirstElementByTagName(e, "PICTURE");
+            if (img == null) {
+                img = DomUtil.getFirstElementByTagName(e, "IMG");
             }
+            if (img == null) {
+                return null;
+            }
+            extractImageAttributes(ie);
+            Element figcaption;
+            Element cap = DomUtil.getFirstElementByTagName(e, "FIGCAPTION");
+            if (cap != null) {
+                // We look for links because some sites put non-caption
+                // elements into <figcaption>. For example: image credit
+                // could contain a link. So we get the whole DOM structure within
+                // <figcaption> only when it contains links, otherwise we get the innerText.
+                figcaption = DomUtil.getFirstElementByTagName(cap, "A") != null ?
+                        cap : createFigcaptionElement(cap);
+            } else {
+                figcaption = createFigcaptionElement(e);
+            }
+            return new WebFigure(img, width, height, imgSrc, figcaption);
         }
-        return null;
+
+        extractImageAttributes(ie);
+        return new WebImage(e, width, height, imgSrc);
     }
 
     private void extractImageAttributes(ImageElement imageElement) {
         // This will get the absolute URL of the image and
         // the displayed image dimension.
         // Try to get lazily-loaded images before falling back to get the src attribute.
         for (String attr : LAZY_IMAGE_ATTRIBUTES) {
             imgSrc = imageElement.getAttribute(attr);
             if (!imgSrc.isEmpty())
                 break;
         }
         if (!imgSrc.isEmpty()) {
             // We cannot trust the dimension if the image is not loaded yet.
             // In some cases there are 1x1 placeholder images.
             width = 0;
             height = 0;
         } else {
             imgSrc = imageElement.getSrc();
             // As an ImageElement is manipulated here, it is possible
             // to get the real dimensions.
             width = imageElement.getWidth();
             height = imageElement.getHeight();
         }
         if (LogUtil.isLoggable(LogUtil.DEBUG_LEVEL_VISIBILITY_INFO)) {
             LogUtil.logToConsole("Extracted WebImage: " + imgSrc);
         }
     }
 
-    private Element getFirstElementByTagName(Element e, String tagName) {
-        NodeList<Element> elements = e.getElementsByTagName(tagName);
-        if (elements.getLength() > 0) {
-            return elements.getItem(0);
-        }
-        return null;
-    }
-
     private Element createFigcaptionElement(Element element) {
         Element figcaption = Document.get().createElement("FIGCAPTION");
         figcaption.setInnerText(DomUtil.getInnerText(element));
         return figcaption;
     }
 }