[Hotword] Add metric to checkbox to track enable/disable of hotwording.

chrome/browser/resources/options/browser_options.html

 <div id="settings" class="page" hidden>
   <header>
     <h1 i18n-content="settingsTitle"></h1>
   </header>
   <include src="reset_profile_settings_banner.html">
 <if expr="not pp_ifdef('chromeos')">
   <include src="sync_section.html">
 </if>
 <if expr="pp_ifdef('chromeos')">
   <section>
@@ skipping 338 matching lines @@
                 pref="cros.device.attestation_for_content_protection_enabled">
             </span>
           </span>
         </span>
       </div>
 </if>
       <div id ="hotword-search" hidden>
         <div class="checkbox">
           <span class="controlled-setting-with-label">
             <input id="hotword-search-enable" pref="hotword.search_enabled"
-                type="checkbox" dialog-pref>
+                metric="Options_HotwordCheckbox" type="checkbox" dialog-pref>

[jochen (gone - plz use gerrit), 2014/02/12 16:20:56]

you didn't run tools/metrics/actions/extract_actions.py --hash and so the metric
is not activated.

[rpetterson, 2014/02/12 18:56:07]

Thank you for pointing that out! I somehow always forget that step. :-/ I'll
send out another CL.

             <span>
               <label for="hotword-search-enable"
                   i18n-values=".innerHTML:hotwordSearchEnable">
               </label>
               <span class="controlled-setting-indicator"
                   pref="hotword.search_enabled" dialog-pref>
               </span>
             </span>
           </span>
         </div>
@@ skipping 513 matching lines @@
     </div>
   </section>
   </div>  <!-- advanced-settings-container -->
   </div>  <!-- advanced-settings -->
   <footer>
     <button id="advanced-settings-expander" class="link-button"
         i18n-content="showAdvancedSettings">
     </button>
   </footer>
   </div>