[Extensions Page MD] Stub out a materialized extensions page

chrome/browser/resources/md_extensions/manager.js

Index: chrome/browser/resources/md_extensions/manager.js
diff --git a/chrome/browser/resources/chromeos/login/gaia_header.js b/chrome/browser/resources/md_extensions/manager.js
similarity index 57%
copy from chrome/browser/resources/chromeos/login/gaia_header.js
copy to chrome/browser/resources/md_extensions/manager.js
index 69898a4e223333b0e8ab849df9582b0c38530546..729ee73338ee94a3eef4921e6ec939f9c40a22d9 100644
--- a/chrome/browser/resources/chromeos/login/gaia_header.js
+++ b/chrome/browser/resources/md_extensions/manager.js
@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-Polymer({
-  is: 'gaia-header',
+cr.define('extensions', function() {
+  var Manager = Polymer({
+    is: 'extensions-manager'
+  });
 
-  properties: {
-    email: String
-  }
+  return {Manager: Manager};
 });