Adding `content_security_policy` to a few sample extensions

chrome/common/extensions/docs/examples/api/webNavigation/basic/popup.css

+/**
+ * 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 {
+  margin: 5px 10px 10px;
+}
+
+h1 {
+  color: #53637D;
+  font: 26px/1.2 Helvetica, sans-serif;
+  font-size: 200%;
+  margin: 0;
+  padding-bottom: 4px;
+  text-shadow: white 0 1px 2px;
+}
+
+body > section {
+  border-radius: 5px;
+  background: -webkit-linear-gradient(rgba(234, 238, 243, 0.2), #EAEEF3),
+  -webkit-linear-gradient(
+  left, #EAEEF3, #EAEEF3 97%, #D3D7DB);
+  font: 14px/1 Arial,Sans Serif;
+  padding: 10px;
+  width:  563px;
+  max-height: 400px;
+  overflow-y: auto;
+  box-shadow: inset 0px 2px 5px rgba(0,0,0,0.5);
+}
+
+body > section > ol {
+  padding: 0;
+  margin: 0;
+  list-style: none inside;
+}
+
+body > section > ol > li {
+  position: relative;
+  margin: 0.5em 0 0.5em 40px;
+}
+
+code {
+  word-wrap: break-word;
+  background: rgba(255,255,0, 0.5);
+}
+
+em {
+  position: absolute;
+  top: 0px;
+  left: -40px;
+  width: 30px;
+  text-align: right;
+  font: 30px/1 Helvetica, sans-serif;
+  font-weight: 700;
+}
+
+p {
+  min-height: 30px;
+  line-height: 1.2;
+}