Consolidates accessing and setting the UMA pref to be within metrics code

chrome/browser/resources/options/browser_options.js

 // Copyright (c) 2012 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.
 
 cr.define('options', function() {
   var OptionsPage = options.OptionsPage;
   var Page = cr.ui.pageManager.Page;
   var PageManager = cr.ui.pageManager.PageManager;
   var ArrayDataModel = cr.ui.ArrayDataModel;
   var RepeatingButton = cr.ui.RepeatingButton;
@@ skipping 357 matching lines @@
         // text" where both starting text and ending text may or may not be
         // present, but the split should always be in three pieces.
         var restartElements =
             $('metrics-reporting-reset-restart').querySelectorAll('*');
         for (var i = 0; i < restartTextFragments.length; i++) {
           restartElements[i].textContent = restartTextFragments[i];
         }
         restartElements[1].onclick = function(event) {
           chrome.send('restartBrowser');
         };
+        // Attach the listener for updating the checkbox and restart button.
         var updateMetricsRestartButton = function() {
           $('metrics-reporting-reset-restart').hidden =
               loadTimeData.getBoolean('metricsReportingEnabledAtStart') ==
                   $('metricsReportingEnabled').checked;
         };
-        Preferences.getInstance().addEventListener(
-            $('metricsReportingEnabled').getAttribute('pref'),
-            updateMetricsRestartButton);
+        $('metricsReportingEnabled').onclick = function(event) {
+          chrome.send('metricsReportingCheckboxChanged',
+              [Boolean(event.currentTarget.checked)]);
+          updateMetricsRestartButton();
+        };
+        $('metricsReportingEnabled').checked =
+            loadTimeData.getBoolean('metricsReportingEnabledAtStart');
         updateMetricsRestartButton();
       }
       $('networkPredictionOptions').onchange = function(event) {
         var value = (event.target.checked ?
             NetworkPredictionOptions.WIFI_ONLY :
             NetworkPredictionOptions.NEVER);
         var metric = event.target.metric;
         Preferences.setIntegerPref(
             'net.network_prediction_options',
             value,
@@ skipping 1095 matching lines @@
       $('factory-reset-section').hidden = false;
     },
 
     /**
      * Set the checked state of the metrics reporting checkbox.
      * @private
      */
     setMetricsReportingCheckboxState_: function(checked, disabled) {
       $('metricsReportingEnabled').checked = checked;
       $('metricsReportingEnabled').disabled = disabled;
+
+      // If checkbox gets disabled then add an attribute for displaying the
+      // special icon. The opposite shouldn't be possible to do.
+      if (disabled) {
+        $('metrics-reporting-disabled-icon').setAttribute('controlled-by',
+                                                          'policy');
+      }
     },
 
     /**
      * @private
      */
     setMetricsReportingSettingVisibility_: function(visible) {
       if (visible)
         $('metricsReportingSetting').style.display = 'block';
       else
         $('metricsReportingSetting').style.display = 'none';
@@ skipping 483 matching lines @@
       }
       button.textContent = loadTimeData.getString(strId);
     };
   }
 
   // Export
   return {
     BrowserOptions: BrowserOptions
   };
 });