Introduce AcccessibilityManager

chrome/browser/resources/options/browser_options.html

 <div id="settings" class="page" hidden>
   <header>
     <h1 i18n-content="settingsTitle"></h1>
   </header>
 <if expr="not pp_ifdef('chromeos')">
   <include src="sync_section.html">
 </if>
 <if expr="pp_ifdef('chromeos')">
   <section>
     <h3 i18n-content="sectionTitleInternet"></h3>
@@ skipping 614 matching lines @@
               </label>
               <span class="controlled-setting-indicator"
                   pref="settings.a11y.enable_menu">
             </span>
           </span>
         </div>
       </div>
       <div class="option-name">
         <div class="checkbox">
           <label>
-            <input id="accessibility-spoken-feedback-check" type="checkbox">
+            <input id="accessibility-spoken-feedback-check"
+                pref="settings.accessibility" type="checkbox">
             <span i18n-content="accessibilitySpokenFeedback"></span>
           </label>
         </div>
       </div>
       <div class="option-name">
         <div class="checkbox">
           <label>
-            <input id="accessibility-high-contrast-check" type="checkbox">
+            <input id="accessibility-high-contrast-check"
+                pref="settings.a11y.high_contrast_enabled" type="checkbox">
             <span i18n-content="accessibilityHighContrast"></span>
           </label>
         </div>
       </div>
       <div class="option-name">
         <div class="checkbox">
           <label>
             <input id="accessibility-screen-magnifier-check"
                 pref="settings.a11y.screen_magnifier" type="checkbox">
             <span i18n-content="accessibilityScreenMagnifier"></span>
@@ skipping 73 matching lines @@
   </button>
 </section>
 </div>  <!-- advanced-settings-container -->
 </div>  <!-- advanced-settings -->
 <footer>
   <button id="advanced-settings-expander" class="link-button"
       i18n-content="showAdvancedSettings">
   </button>
 </footer>
 </div>