Add documentation for filtered events.

chrome/common/extensions/docs/server2/templates/intros/events.html

Index: chrome/common/extensions/docs/server2/templates/intros/events.html
diff --git a/chrome/common/extensions/docs/server2/templates/intros/events.html b/chrome/common/extensions/docs/server2/templates/intros/events.html
index 709c6f17b88176977a2385e938093819097ea227..239380439372c24939915a942cc325bc3ce00d74 100644
--- a/chrome/common/extensions/docs/server2/templates/intros/events.html
+++ b/chrome/common/extensions/docs/server2/templates/intros/events.html
@@ -155,4 +155,48 @@ The <code>details</code> parameter passed to the <code>calback()</code> function
 refers to an array of rules including filled optional parameters.
 </p>
 </div>
+{{/is_apps}}
+
+{{^is_apps}}
+<div class="doc-family extensions">
+<h2 id="filtered">Filtered events</h2>
+
+<p>Filtered events are a mechanism that allows listeners to specify a subset of
+events that they are interested in. A listener that makes use of a filter won't
+be invoked for events that don't pass the filter, which makes the listening
+code more declarative and efficient - an <a href="event_pages.html">event
+  page</a> page need not be woken up to handle events it doesn't care
+about.</p>
+
+<p>Filtered events are intended to allow a transition from manual filtering
+code like this:</p>
+
+<pre>
+chrome.webNavigation.onCommitted.addListener(function(e) {
+  if (hasHostSuffix(e.url, 'google.com') ||
+      hasHostSuffix(e.url, 'google.com.au')) {
+    // ...
+  }
+});
+</pre>
+
+<p>into this:</p>
+
+<pre>
+chrome.webNavigation.onCommitted.addListener(function(e) {
+  // ...
+}, {url: [{hostSuffix: 'google.com'},
+          {hostSuffix: 'google.com.au'}]});
+</pre>
+
+<p>Events support specific filters that are meaningful to that event. The list
+of filters that an event supports will be listed in the documentation for that
+event in the "filters" section.</p>
+
+<p>When matching URLs (as in the example above), event filters support the same
+URL matching capabilities as expressable with a <a
+  href="events.html#type-UrlFilter">UrlFilter</a>, except for scheme and port
+matching.</p>
+
+</div>
 {{/is_apps}}