Revert of Revert CL 117933003. Re-add resource speculative prefetching code.

chrome/browser/resources/predictors/resource_prefetch_predictor.js

-// Copyright 2014 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.
-
-/**
- * Requests the database from the backend.
- */
-function requestResourcePrefetchPredictorDb() {
-  chrome.send('requestResourcePrefetchPredictorDb');
-}
-
-/**
- * Callback from backend with the database contents. Sets up some globals and
- * calls to create the UI.
- * @param {Dictionary} database Information about ResourcePrefetchPredictor
- *     including the database as a flattened list, a boolean indicating if the
- *     system is enabled.
- */
-function updateResourcePrefetchPredictorDb(database) {
-  updateResourcePrefetchPredictorDbView(database);
-}
-
-/**
- * Truncates the string to keep the database readable.
- * @param {string} str The string to truncate.
- * @return {string} The truncated string.
- */
-function truncateString(str) {
-  return str.length < 100 ? str : str.substring(0, 99);
-}
-
-/**
- * Updates the table from the database.
- * @param {Dictionary} database Information about ResourcePrefetchPredictor
- *     including the database as a flattened list, a boolean indicating if the
- *     system is enabled and the current hit weight.
- */
-function updateResourcePrefetchPredictorDbView(database) {
-  if (!database.enabled) {
-    $('rpp_enabled').style.display = 'none';
-    $('rpp_disabled').style.display = 'block';
-    return;
-  } else {
-    $('rpp_enabled').style.display = 'block';
-    $('rpp_disabled').style.display = 'none';
-  }
-
-  var hasUrlData = database.url_db && database.url_db.length > 0;
-  var hasHostData = database.host_db && database.host_db.length > 0;
-
-  if (hasUrlData)
-    renderCacheData($('rpp_url_body'), database.url_db);
-  if (hasHostData)
-    renderCacheData($('rpp_host_body'), database.host_db);
-}
-
-/**
- * Renders cache data for URL or host based data.
- * @param {HTMLElement} body element of table to render into.
- * @param {Dictionary} database to render.
- */
-function renderCacheData(body, database) {
-  body.textContent = '';
-  for (var i = 0; i < database.length; ++i) {
-    var main = database[i];
-
-    for (var j = 0; j < main.resources.length; ++j) {
-      var resource = main.resources[j];
-      var row = document.createElement('tr');
-
-      if (j == 0) {
-        var t = document.createElement('td');
-        t.rowSpan = main.resources.length;
-        t.textContent = truncateString(main.main_frame_url);
-        t.className = 'last';
-        row.appendChild(t);
-      }
-
-      if (j == main.resources.length - 1)
-        row.className = 'last';
-
-      row.appendChild(document.createElement('td')).textContent =
-          truncateString(resource.resource_url);
-      row.appendChild(document.createElement('td')).textContent =
-          resource.resource_type;
-      row.appendChild(document.createElement('td')).textContent =
-          resource.number_of_hits;
-      row.appendChild(document.createElement('td')).textContent =
-          resource.number_of_misses;
-      row.appendChild(document.createElement('td')).textContent =
-          resource.consecutive_misses;
-      row.appendChild(document.createElement('td')).textContent =
-          resource.position;
-      row.appendChild(document.createElement('td')).textContent =
-          resource.score;
-      body.appendChild(row);
-    }
-  }
-}
-
-document.addEventListener('DOMContentLoaded',
-                          requestResourcePrefetchPredictorDb);