Support <picture> in image extraction

javatests/org/chromium/distiller/webdocument/WebTableTest.java

Index: javatests/org/chromium/distiller/webdocument/WebTableTest.java
diff --git a/javatests/org/chromium/distiller/webdocument/WebTableTest.java b/javatests/org/chromium/distiller/webdocument/WebTableTest.java
index 0b3e460bf8f7026b4b348cd093fc3454080d3b7c..c7dd0548610e5c3fff476020335d4371a82a1c7d 100644
--- a/javatests/org/chromium/distiller/webdocument/WebTableTest.java
+++ b/javatests/org/chromium/distiller/webdocument/WebTableTest.java
@@ -13,12 +13,44 @@ import com.google.gwt.dom.client.Document;
 import com.google.gwt.dom.client.Element;
 
 public class WebTableTest extends DomDistillerJsTestCase {
+    public void testGetImageUrlList() {
+        mHead.setInnerHTML("<base href=\"http://example.com/\">");
+        Element table = Document.get().createTableElement();
+
+        String html =
+                "<tbody>" +
+                  "<tr>" +
+                    "<td><img src=\"http://example.com/table.png\" " +
+                             "srcset=\"image100 100w, //example.org/image300 300w\"></td>" +
+                    "<td>" +
+                      "<picture>" +
+                        "<source srcset=\"image200 200w, //example.org/image400 400w\">" +
+                        "<img>" +
+                      "</picture>" +
+                    "</td>" +
+                  "</tr>" +
+                "</tbody>";
+
+        table.setInnerHTML(html);
+        mBody.appendChild(table);
+
+        WebTable webTable = new WebTable(table);
+        List<String> urls = webTable.getImageUrlList();
+        assertEquals(5, urls.size());
+        assertEquals("http://example.com/table.png", urls.get(0));
+        assertEquals("http://example.com/image100", urls.get(1));
+        assertEquals("http://example.org/image300", urls.get(2));
+        assertEquals("http://example.com/image200", urls.get(3));
+        assertEquals("http://example.org/image400", urls.get(4));
+    }
+
     public void testGenerateOutput() {
         Element table = Document.get().createTableElement();
         String html = "<tbody>" +
                           "<tr>" +
                               "<td>row1col1</td>" +
                               "<td><img src=\"http://example.com/table.png\"></td>" +
+                              "<td><picture><img></picture></td>" +
                           "</tr>" +
                       "</tbody>";
         table.setInnerHTML(html);
@@ -29,6 +61,8 @@ public class WebTableTest extends DomDistillerJsTestCase {
 
         // Output should be the same as the input in this case.
         assertEquals("<table>" + html + "</table>", TestUtil.removeAllDirAttributes(got));
+
+        // Test getImageUrlList() as well.
         List<String> imgUrls = webTable.getImageUrlList();
         assertEquals(1, imgUrls.size());
         assertEquals("http://example.com/table.png", imgUrls.get(0));