Remove experimental permission from infobars API and moving it to dev channel

chrome/common/extensions/docs/templates/intros/infobars.html

 <p>
 The infobars API allows you to add a
 horizontal panel just above a tab's contents,
 as the following screenshot shows.
 </p>
 
 <p>
 <img src="{{static}}/images/infobar.png"
   width="566" height="150"
   alt="An infobar asking whether the user wants to translate the current page" />
@@ skipping 10 matching lines @@
 You implement the content of your
 infobar using HTML. Because infobars are ordinary pages inside an extension,
 they can
 <a href="overview.html#pageComm">communicate with other extension pages</a>.
 </p>
 
 
 <h2 id="manifest">Manifest</h2>
 
 <p>
-The infobars API is currently
-experimental, so you must declare the "experimental"
-permission to use it. Also, you should specify
+The infobars API is avaiable under "infobars"
+permission and dev channel only. Also, you should specify
 a 16x16-pixel icon for display next to your infobar.
 For example:
 </p>
 
 <pre>{
   "name": "Andy's infobar extension",
   "version": "1.0",
-  <b>"permissions": ["experimental"],</b>
+  <b>"permissions": ["infobars"],</b>
   <b>"icons": {</b>
     <b>"16": "16.png"</b>
   <b>},</b>
   "background": {
     "scripts": ["background.js"]
   }
-}</pre>
+}</pre>