Added "Use an autoconfiguration URL" checkbox in proxy tab

chrome/browser/resources/options/chromeos/internet_detail.html

 <div id="details-internet-page" class="page" hidden>
   <div class="close-button"></div>
   <!-- Network header -->
   <div id="network-details-header">
     <div id="network-details-title"></div>
     <div id="network-details-subtitle">
       <span id="network-details-subtitle-status"></span>
       <span id="network-details-subtitle-separator"> - </span>
       <span id="network-details-subtitle-type"></span>
     </div>
@@ skipping 632 matching lines @@
             </tr>
           </table>
         </div>
         <div class="radio">
           <label>
             <input id="auto-proxy" type="radio" name="proxytype" value="3"
                 pref="cros.session.proxy.type">
             <span i18n-content="proxyAutomatic"></span>
           </label>
         </div>
+        <div class="checkbox">
+          <label>
+            <input id="proxy-use-pac-url" type="checkbox"
+                pref="cros.session.proxy.usepacurl">
+            <span i18n-content="proxyUseConfigUrl"></span>
+          </label>
+        </div>
         <div>
           <label>
-            <div i18n-content="proxyConfigUrl"></div>
-            <input id="proxy-config" type="url" size="50"
+            <input id="proxy-pac-url" type="url" size="50"
                 pref="cros.session.proxy.pacurl">
           </label>
         </div>
         <div id="advanced-config">
           <h3 i18n-content="advancedProxyConfig"></h3>
           <div class="option vbox flex">
             <div i18n-content="proxyBypass"></div>
             <list id="ignored-host-list"></list>
             <input id="new-host" type="url" size="30">
             <button id="add-host" i18n-content="addHost"></button>
@@ skipping 13 matching lines @@
       </button>
       <button id="details-internet-disconnect" i18n-content="disconnectButton">
       </button>
       <button id="activate-details" i18n-content="activateButton"></button>
       <button id="buyplan-details" i18n-content="buyplanButton"></button>
       <button id="view-account-details" i18n-content="viewAccountButton">
       </button>
     </div>
   </div>
 </div>