[SiteEngagement WebUI] Replace C++ browser test with JS version.

chrome/browser/resources/engagement/site_engagement.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.
 
 'use strict';
 
 // Allow a function to be provided by tests, which will be called when
 // the page has been populated with site engagement details.
 var resolvePageIsPopulated = null;
 var pageIsPopulatedPromise = new Promise((resolve, reject) => {
@@ skipping 102 matching lines @@
 
     /**
      * Sets the base engagement score when a score input is changed.
      * Resets the length of engagement-bar-cell to match the new score.
      * Also resets the update interval.
      * @param {string} origin The origin of the engagement score to set.
      * @param {Event} e
      */
     function handleBaseScoreChange(origin, e) {
       var baseScoreInput = e.target;
-      uiHandler.setSiteEngagementScoreForUrl(origin, baseScoreInput.value);
+      uiHandler.setSiteEngagementBaseScoreForUrl(origin, baseScoreInput.value);
       baseScoreInput.barCellRef.style.width = (baseScoreInput.value * 4) + 'px';
       baseScoreInput.blur();
       enableAutoupdate();
     }
 
     /**
      * Remove all rows from the engagement table.
      */
     function clearTable() {
       engagementTableBody.innerHTML = '';
@@ skipping 54 matching lines @@
         info.base_score = roundScore(info.base_score);
         info.installed_bonus = roundScore(info.installed_bonus);
         info.notifications_bonus = roundScore(info.notifications_bonus);
         info.total_score = roundScore(info.total_score);
 
         // Collate the bonuses into a value for the bonus_score column.
         info.bonus_score = info.installed_bonus + info.notifications_bonus;
 
         engagementTableBody.appendChild(createRow(info));
       });
-
-      resolvePageIsPopulated();
     }
 
     /**
      * Retrieve site engagement info and render the engagement table.
      */
     function updateEngagementTable() {
       // Populate engagement table.
       uiHandler.getSiteEngagementDetails().then((response) => {
         info = response.info;
         renderTable(info);
+        resolvePageIsPopulated();
       });
     };
 
     updateEngagementTable();
     enableAutoupdate();
   };
 });