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

chrome/browser/resources/options/browser_options.html

 <div id="settings" class="page" hidden>
   <header>
     <h1 i18n-content="settingsTitle"></h1>
   </header>
   <include src="automatic_settings_reset_banner.html">
 <if expr="chromeos">
   <include src="secondary_user_banner.html">
   <section>
     <div id="network-section-header" class="section-header">
       <h3 i18n-content="sectionTitleInternet"></h3>
@@ skipping 349 matching lines @@
         <label>
           <input id="metricsReportingEnabled"
               pref="cros.metrics.reportingEnabled" type="checkbox">
           <span i18n-content="enableLogging"></span>
         </label>
         <span class="controlled-setting-indicator"
             pref="cros.metrics.reportingEnabled"></span>
 </if>
 <if expr="not chromeos">
         <label>
-          <input id="metricsReportingEnabled"
-              pref="user_experience_metrics.reporting_enabled" type="checkbox">
+          <input id="metricsReportingEnabled" type="checkbox">
           <span i18n-content="enableLogging">
         </label>
-        <span class="controlled-setting-indicator"
-            pref="user_experience_metrics.reporting_enabled">
+        <span id="metrics-reporting-disabled-icon"
+            class="controlled-setting-indicator">
         </span>
         <span id="metrics-reporting-reset-restart">
           <!-- Text filled by JavaScript -->
           <span></span><button class=
               "link-button standalone-link-button"></button><span></span>
         </span>
 </if>
       </div>
 </if>  <!-- _google_chrome -->
       <div class="checkbox">
@@ skipping 484 matching lines @@
     <button id="advanced-settings-expander" class="link-button"
         i18n-content="showAdvancedSettings">
     </button>
 <if expr="chromeos">
     <button id="version-button" class="link-button" hidden
         i18n-content="browserVersion">
     </button>
 </if>
   </footer>
 </div>