Add getSelf method to management API to use without the "management" permission.

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

 <h2 id="manifest">Manifest</h2>
 
 <p>You must declare the "management" permission
 in the <a href="manifest">extension manifest</a>
 to use the management API.
 For example:</p>
 <pre data-filename="manifest.json">
 {
   "name": "My extension",
   ...
   <b>"permissions": [
     "management"
   ]</b>,
   ...
 }</pre>
 
 <p>
-$(ref:management.getPermissionWarningsByManifest) and
-$(ref:management.uninstallSelf) do not require the management permission
+$(ref:management.getPermissionWarningsByManifest),
+$(ref:management.uninstallSelf), and $(ref:management.getSelf) do not require
+the management permission.
 </p>