Revert "Revert of Refactor get_salient_image_url.js to use DocumentImageExtractor"

chrome/browser/resources/get_salient_image_url.js

-// 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.
-
-/*
- * Looks on the page to find the image that could be the most representative
- * one.
- */
-(function() {
-  // Extract the referrer policy from the page.
-  var referrerPolicy = 'default';
-  var metaTags = document.getElementsByTagName('meta');
-  for (var i = 0; i < metaTags.length; ++i) {
-    if (metaTags[i].name.toLowerCase() == 'referrer') {
-      referrerPolicy = metaTags[i].content.toLowerCase();
-      break;
-    }
-  }
-
-  // See what to use for JSON. Some pages use a library that overrides JSON.
-  var jsonEncoder = JSON.stringify;
-  if (!jsonEncoder)
-    jsonEncoder = JSON.encode;
-
-  // First look if there is an Open Graph Image property available.
-  var ogImage = document.querySelector('meta[property=\"og:image\"]');
-  if (ogImage) {
-    // Checks that the url in ogImage has a path that contains more than just a
-    // simple '/'.
-    var url = ogImage.content;
-    var location = document.createElement('a');
-    location.href = url;
-    if (location.pathname.length > 1) {
-      return jsonEncoder({
-        'imageUrl': url,
-        'referrerPolicy': referrerPolicy
-      });
-    }
-  }
-
-  // Iterates through the images on the page, find the largest one that doesn't
-  // look like a banner.
-  var maxPointSize = 0;
-  var maxImage = null;
-
-  var images = document.getElementsByTagName('img');
-  for (var i = 0; i < images.length; i++) {
-    var currentImage = images[i];
-    var aspectRatio = currentImage.width / currentImage.height;
-    if (aspectRatio >= 2.4 || aspectRatio <= 0.5)
-      continue;  // Skip weirdly shaped images. Those are ads or headers.
-    var pointSize = currentImage.width * currentImage.height;
-    if (pointSize > maxPointSize) {
-      maxPointSize = pointSize;
-      maxImage = currentImage;
-    }
-  }
-
-  // Only keep images larger than 320*160.
-  if (maxPointSize <= 51200.0 || maxImage === null)
-    return '';
-
-  return jsonEncoder({
-    'imageUrl': maxImage.src,
-    'referrerPolicy': referrerPolicy
-  });
-})();