Extension docs: Update whats_new.html for M21.

chrome/common/extensions/docs/server2/templates/articles/whats_new.html

 <h1>What's New in Extensions?</h1>
 <!--  -->
 
 <p>
 This page lists the API and manifest changes
 made in recent releases.
 </p>
 
 <ul>
+  <li> <a href="#21">Google Chrome 21</a> </li>
   <li> <a href="#20">Google Chrome 20</a> </li>
   <li> <a href="#19">Google Chrome 19</a> </li>
   <li> <a href="#18">Google Chrome 18</a> </li>
   <li> <a href="#17">Google Chrome 17</a> </li>
   <li> <a href="#16">Google Chrome 16</a> </li>
   <li> <a href="#15">Google Chrome 15</a> </li>
   <li> <a href="#14">Google Chrome 14</a> </li>
   <li> <a href="#13">Google Chrome 13</a> </li>
   <li> <a href="#12">Google Chrome 12</a> </li>
   <li> <a href="#11">Google Chrome 11</a> </li>
   <li> <a href="#10">Google Chrome 10</a> </li>
   <li> <a href="#9">Google Chrome 9</a> </li>
   <li> <a href="#8">Google Chrome 8</a> </li>
   <li> <a href="#7">Google Chrome 7</a> </li>
   <li> <a href="#6">Google Chrome 6</a> </li>
 </ul>
 
-<p class="note">
-  <strong>New version of packaged apps:</strong><br>
-  There's a new version of
-  <a href="http://developer.chrome.com/trunk/apps/about_apps.html">packaged apps</a>
-  in the <a href="http://dev.chromium.org/getting-involved/dev-channel?">dev channel</a>.
-</p>
+<h2 id="21"> Google Chrome 21 </h2>
 
-<p>
-In addition to the changes listed below,
-check out the
-<a href="experimental.html">experimental APIs</a>.
-</p>
+<h4> New Features </h4>
+  <ul>
+    <li>The <a href="manifest.html#sandbox">sandbox manifest entry</a> allows
+      you to define some pages within your extension that are automatically run
+      in a low-privilege sandbox. This sandbox is not bound by the
+      <a href="manifest.html#content_security_policy"
+      >content_security_policy</a>.
+
+    <li>The <a href="input.ime.html">IME</a> API allows extensions to implement
+      <a href="http://en.wikipedia.org/wiki/Input_method">input method
+      editors</a> on Chrome OS.
+  </ul>
+
+<h4> Additions to Existing Features </h4>
+  <ul>
+    <li>The events in the <a href="webNavigation.html">Web Navigation API</a>
+      now accept <a href="events.html#declarative">filters</a> which limit the
+      URLs they fire on.
+    <li>The <code><a href="types.html#method-types.ChromeSetting-set"
+      >ChromeSetting.set</a></code> method now has a
+      <code>regular_only</code> scope.
+    <li>The <a href="browsingData.html#type-browsingData.RemovalOptions"
+      >browsingData.RemovalOptions</a> now has an <code>originTypes</code>
+      property.
+    <li>The <code><a href="management.html#method-uninstall"
+      >management.uninstall()</a></code> method now has a <code
+      >showConfirmDialog</code> parameter.
+    <li>The <code><a href="contextMenus.html#method-create"
+      >contextMenus.create()</a></code> method now allows you to specify unique
+      IDs for each item. This is intended to be used with the new
+      <code><a href="contextMenus.html#event-onClicked"
+      >contextMenus.onClicked</a></code> event, to distinguish the clicked item.
+    <li>The <code><a href="browserAction.html#method-setIcon"
+      >browserAction.setIcon()</a></code> and
+      <code><a href="pageAction.html#method-setIcon"
+      >pageAction.setIcon()</a></code> methods now accept optional callbacks.
+    <li>The <code><a href="privacy.html#property-websites"
+      >privacy.website</a></code> namespace now has a <code
+      >protectedContentEnabled</code> property.
+    <li>The <code>index</code> parameter to the <a href="tabs.html#method-move"
+      >tabs.move()</a></code> method now accepts <code>-1</code> to indicate
+      that the tab should be placed at the end.
+    <li>The <code>windowId</code> parameter to the
+      <code><a href="tabs.html#method-highlight">tabs.highlight()</a></code>
+      method is now optional.
+  </ul>
 
 <h2 id="20"> Google Chrome 20 </h2>
 
 <h4> New APIs </h4>
   <ul>
     <li>The
       <a href="storage.html">storage API</a>
       lets you store, retrieve, and
       track changes to user data.</li>
   </ul>
@@ skipping 538 matching lines @@
 <h4> Manifest changes </h4>
   <ul>
     <li>The <a href="manifest.html#geolocation">geolocation</a> permission
       gives an extension access to the user's physical location.
     <li><a href="match_patterns.html">Match patterns</a> can now select all
       schemes or all URLs.
     <li>Access to file:/// URLs no longer triggers the "access to your machine"
       security warning, but now requires user opt-in from the extensions
       management page.
   </ul>