[Extensions] Remove the Infobar API

chrome/common/extensions/docs/templates/articles/manifest/icons.html

 <h1 id="icons">Manifest - Icons</h1>
 
 <p>
 One or more icons that represent the extension, app, or theme.
 You should always provide a 128x128 icon;
 it's used during installation and by the Chrome Web Store.
 Extensions should also provide a 48x48 icon,
 which is used in the extensions management page
 (chrome://extensions).
 You can also specify a 16x16 icon to be used as the favicon
 for an extension's pages.
-The 16x16 icon is also displayed in the experimental extension
-<a href="http://developer.chrome.com/extensions/infobars">infobar</a>
-feature.
-</p>
 
 <p>
 Icons should generally be in PNG format,
 because PNG has the best support for transparency.
 They can, however, be in any format supported by WebKit,
 including BMP, GIF, ICO, and JPEG.
 Here's an example of specifying the icons:
 </p>
 
 <pre data-filename="manifest.json">
@@ skipping 13 matching lines @@
 <p>
 If you upload your extension, app, or theme using the
 <a href="https://chrome.google.com/webstore/developer/dashboard">Chrome Developer Dashboard</a>,
 you'll need to upload additional images,
 including at least one screenshot of your extension.
 For more information,
 see the
 <a href="http://code.google.com/chrome/webstore/">Chrome Web Store
 developer documentation</a>.
 </p>