Adding `content_security_policy` to a few sample extensions.

chrome/common/extensions/docs/examples/api/notifications/error.html

Index: chrome/common/extensions/docs/examples/api/notifications/error.html
diff --git a/chrome/common/extensions/docs/examples/api/notifications/error.html b/chrome/common/extensions/docs/examples/api/notifications/error.html
deleted file mode 100644
index 1a20c4298b5facae7370566693c39b6e665eb64b..0000000000000000000000000000000000000000
--- a/chrome/common/extensions/docs/examples/api/notifications/error.html
+++ /dev/null
@@ -1,41 +0,0 @@
-<!--
-  An error page for browsers that don't implement notifications.
-
-  Copyright 2010 the Chromium Authors
-
-  Use of this source code is governed by a BSD-style license that can be found
-  in the "LICENSE" file.
-
-  Brian Kennish <bkennish@chromium.org>
--->
-<title>Notification Demo</title>
-<style>
-  /* Clone the look and feel of "chrome://" pages. */
-  body {
-    margin: 10px;
-    font: 84% Arial, sans-serif
-  }
-
-  h1 { font-size: 156% }
-
-  h1 img {
-    margin: 1px 5px 0 1px;
-    vertical-align: middle
-  }
-
-  h2 {
-    border-top: 1px solid #9cc2ef;
-    background-color: #ebeff9;
-    padding: 3px 5px;
-    font-size: 100%
-  }
-</style>
-<h1>
-  <img src="64.png" alt="Toast">
-  Notification Demo
-</h1>
-<h2>Error</h2>
-<p>
-  Desktop notifications are supported only by Google Chrome 4 and up on Windows
-  and Google Chrome 5 and up on the Mac and Linux.
-</p>