Deprecate most of gaia_auth extension

chrome/browser/resources/gaia_auth/main.css

Index: chrome/browser/resources/gaia_auth/main.css
diff --git a/chrome/browser/resources/gaia_auth/main.css b/chrome/browser/resources/gaia_auth/main.css
deleted file mode 100644
index 1bbc0d6d8ebf8225ce8d8b8a15e7200d65dfaff3..0000000000000000000000000000000000000000
--- a/chrome/browser/resources/gaia_auth/main.css
+++ /dev/null
@@ -1,24 +0,0 @@
-/* Copyright 2013 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. */
-
-html,
-body,
-iframe {
-  height: 100%;
-  margin: 0;
-  padding: 0;
-  width: 100%;
-}
-
-iframe {
-  overflow: hidden;
-}
-
-webview {
-  display: inline-block;
-  height: 100%;
-  margin: 0;
-  padding: 0;
-  width: 100%;
-}