Add chrome://usb-internals page for adding and removing test devices.

chrome/browser/resources/usb_internals/usb_internals.css

Index: chrome/browser/resources/usb_internals/usb_internals.css
diff --git a/chrome/browser/resources/usb_internals/usb_internals.css b/chrome/browser/resources/usb_internals/usb_internals.css
new file mode 100644
index 0000000000000000000000000000000000000000..c11885b6a0da026ba62ea8bdc22c8a9e7d13a538
--- /dev/null
+++ b/chrome/browser/resources/usb_internals/usb_internals.css
@@ -0,0 +1,33 @@
+/* Copyright 2016 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.
+ */
+
+table.styled-table {
+  border-collapse: collapse;
+}
+
+table.styled-table,
+.styled-table th,
+.styled-table td {
+  border: 1px solid #777;
+  padding-left: 4px;
+  padding-right: 4px;
+}
+
+.styled-table th {
+  text-align: left;
+}
+
+.page-section {
+  border: 1px solid #777;
+  padding: 4px;
+}
+
+.action-success {
+  color: green;
+}
+
+.action-failure {
+  color: red;
+}