Add sample extension that allows setting plugin-specific content settings.

chrome/common/extensions/docs/examples/extensions/plugin_settings/css/plugin_list.css

Index: chrome/common/extensions/docs/examples/extensions/plugin_settings/css/plugin_list.css
diff --git a/chrome/common/extensions/docs/examples/extensions/plugin_settings/css/plugin_list.css b/chrome/common/extensions/docs/examples/extensions/plugin_settings/css/plugin_list.css
new file mode 100644
index 0000000000000000000000000000000000000000..225bd3c6230c839ebf8cdc1d63535836a8d23522
--- /dev/null
+++ b/chrome/common/extensions/docs/examples/extensions/plugin_settings/css/plugin_list.css
@@ -0,0 +1,85 @@
+/*
+Copyright (c) 2011 The Chromium Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+*/
+
+body {
+  font-family: Helvetica, sans-serif;
+  background-color: white;
+  color: black;
+  margin: 10px;
+}
+
+.plugin-list {
+  border: 1px solid #d9d9d9;
+  border-radius: 2px;
+  width: 517px;
+}
+
+.plugin-list > li {
+  padding: 3px;
+}
+
+.plugin-name {
+  display: inline-block;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  font-weight: bold;
+}
+
+.num-rules:before {
+  content: ' ';
+}
+
+.plugin-show-details .num-rules {
+  display: none;
+}
+
+.plugin-description {
+  display: inline-block;
+  -webkit-padding-start: 7px;
+  width: auto;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  font-size: 95%;
+}
+
+.plugin-details {
+  -webkit-transition: height .5s ease-in-out;
+  background: #f5f8f8;
+  border: 1px solid #b2b2b2;
+  border-radius: 5px;
+  padding: 5px;
+  height: 0;
+  width: 500px;
+  opacity: 0;
+}
+
+.plugin-measure-details .plugin-details {
+  -webkit-transition: none;
+  height: auto;
+  visibility: hidden;
+}
+
+li.plugin-show-details {
+  height: auto;
+}
+
+.plugin-show-details .plugin-description {
+  height: auto;
+}
+
+.plugin-show-details .plugin-details {
+  opacity: 1;
+  height: auto;
+}
+
+.column-headers {
+  -webkit-margin-start: 17px;
+  display: -webkit-box;
+}
+
+.column-headers > div {
+  font-weight: bold;
+}