Install warning message code for extensions that use chrome.mdns API.

chrome/common/extensions/docs/templates/articles/permission_warnings.html

 <h1>Permission Warnings</h1>
 
 
 <!--
 NOTE: When this doc is updated, the online help should also be updated:
 http://www.google.com/support/chrome_webstore/bin/answer.py?hl=en&answer=186213
 
 We should periodically look at
 http://src.chromium.org/viewvc/chrome/trunk/src/chrome/app/generated_resources.grd?view=markup
 to make sure that we're covering all messages. Search for
@@ skipping 304 matching lines @@
     "management" permission
   </td>
   <td>
     The "management" permission is required by the
     <a href="management"><code>chrome.management</code></a> module.
   </td>
 </tr>
 
 <tr>
   <td style="font-weight:bold">
+    <!-- IDS_EXTENSION_PROMPT_WARNING_MDNS -->
+    Discover devices on your local network
+  </td>
+  <td>
+    "mdns" permission
+  </td>
+  <td>
+    The "mdns" permission is required by the
+    <a href="mdns"><code>chrome.mdns</code></a> module.
+  </td>
+</tr>
+
+<tr>
+  <td style="font-weight:bold">
     <!-- IDS_EXTENSION_PROMPT_WARNING_GEOLOCATION -->
     Detect your physical location
   </td>
   <td>
     "geolocation" permission
   </td>
   <td>
     Allows the extension to use the proposed HTML5
     <a href="http://dev.w3.org/geo/api/spec-source.html">geolocation API</a>
     without prompting the user for permission.
@@ skipping 122 matching lines @@
 by clicking the <b>chrome://extensions</b> page's
 <b>Update extensions now</b> button.
 </p>
 
 <h2 id="api">API</h2>
 
 <p>
 You can get a list of permission warnings for any manifest with
 $(ref:management.getPermissionWarningsByManifest).
 </p>