[MD Extensions] Merge CSS into html files

chrome/browser/resources/md_extensions/item_list.css

Index: chrome/browser/resources/md_extensions/item_list.css
diff --git a/chrome/browser/resources/md_extensions/item_list.css b/chrome/browser/resources/md_extensions/item_list.css
deleted file mode 100644
index 4b8f0a688c6fb10f107017b7d1d3eb5e8026dbd0..0000000000000000000000000000000000000000
--- a/chrome/browser/resources/md_extensions/item_list.css
+++ /dev/null
@@ -1,16 +0,0 @@
-/* Copyright 2015 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. */
-
-:host {
-  @apply(--layout-vertical);
-}
-
-iron-list {
-  @apply(--layout-flex);
-  margin-top: 18px;
-}
-
-.wrapper {
-  padding: 6px;
-}