First cut at custom user style sheets.

chrome/common/notification_type.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_COMMON_NOTIFICATION_TYPE_H_
 #define CHROME_COMMON_NOTIFICATION_TYPE_H_
 
 // This file describes various types used to describe and filter notifications
 // that pass through the NotificationService.
 //
@@ skipping 644 matching lines @@
 
     PERSONALIZATION,
     PERSONALIZATION_CREATED,
 
     // User Scripts ------------------------------------------------------------
 
     // Sent when there are new user scripts available.  The details are a
     // pointer to SharedMemory containing the new scripts.
     USER_SCRIPTS_UPDATED,
 
+    // User Style Sheet --------------------------------------------------------
+
+    // Sent when the user style sheet has changed.
+    USER_STYLE_SHEET_UPDATED,
+
     // Extensions --------------------------------------------------------------
 
     // Sent when the known installed extensions have all been loaded.  In
     // testing scenarios this can happen multiple times if extensions are
     // unloaded and reloaded. The source is a Profile.
     EXTENSIONS_READY,
 
     // Sent when a new extension is loaded. The details are an Extension, and
     // the source is a Profile.
     EXTENSION_LOADED,
@@ skipping 209 matching lines @@
 };
 
 inline bool operator==(NotificationType::Type a, NotificationType b) {
   return a == b.value;
 }
 inline bool operator!=(NotificationType::Type a, NotificationType b) {
   return a != b.value;
 }
 
 #endif  // CHROME_COMMON_NOTIFICATION_TYPE_H_