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

chrome/browser/resources/options/browser_options.js

Index: chrome/browser/resources/options/browser_options.js
diff --git a/chrome/browser/resources/options/browser_options.js b/chrome/browser/resources/options/browser_options.js
index aea83e6ea6f85d6c80d20e75eed3bac97f7a7da1..890dd72a0518a936dabef380a128985a1c0ddbb9 100644
--- a/chrome/browser/resources/options/browser_options.js
+++ b/chrome/browser/resources/options/browser_options.js
@@ -388,14 +388,19 @@ cr.define('options', function() {
         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) {
@@ -1519,6 +1524,13 @@ cr.define('options', function() {
     setMetricsReportingCheckboxState_: function(checked, disabled) {
       $('metricsReportingEnabled').checked = checked;
       $('metricsReportingEnabled').disabled = disabled;
+
+      // if checkbox gets disabled then add a attribute for displaying the

[Alexei Svitkine (slow), 2014/09/09 20:30:05]

Nit: Capitalize; also, "a attribute" -> "an attribute"

[gayane -on leave until 09-2017, 2014/09/10 16:58:27]

Done.

+      // special icon. The opposite shouldn't be possible to do.
+      if (disabled) {
+        $('metrics-reporting-disabled-icon').setAttribute('controlled-by',
+                                                          'policy');
+      }
     },
 
     /**