Add a chrome://webapks page.

chrome/browser/resources/webapks/about_webapks.css

Index: chrome/browser/resources/webapks/about_webapks.css
diff --git a/chrome/browser/resources/webapks/about_webapks.css b/chrome/browser/resources/webapks/about_webapks.css
new file mode 100644
index 0000000000000000000000000000000000000000..11ceac58b610911232e92e4a3b330029ddfb36b4
--- /dev/null
+++ b/chrome/browser/resources/webapks/about_webapks.css
@@ -0,0 +1,48 @@
+/* Copyright 2017 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 {
+  background-color: white;
+  color: black;
+  font-size: 100%;
+  margin: 0;
+}
+
+#outer {
+  margin-left: auto;
+  margin-right: auto;
+  margin-top: 10px;
+  width: 90%;
+}
+
+.label {
+  -webkit-padding-end: 5px;
+  font-size: 1.5em;
+  font-weight: bold;
+  text-align: start;
+  white-space: nowrap;
+}
+
+#logo {
+  display: block;
+  margin-bottom: 10px;
+  margin-left: auto;
+  margin-right: auto;
+}
+
+.app-name {
+  -webkit-padding-end: 5px;
+  display: block;
+  font-size: 1.2em;
+  font-weight: bold;
+  margin-top: 20px;
+  white-space: nowrap;
+}
+
+.app-property-label {
+  -webkit-padding-end: 5px;
+  font-weight: bold;
+  text-align: start;
+  white-space: nowrap;
+}