Implement sidebar support for extension action popups

chrome/browser/chrome_notification_types.h

Index: chrome/browser/chrome_notification_types.h
diff --git a/chrome/browser/chrome_notification_types.h b/chrome/browser/chrome_notification_types.h
index 424dbd751ba8a4182eb4ba2ba5aa91d9ad24966f..12f761ff0988ae19bd4d7da07142ce7558eb73d5 100644
--- a/chrome/browser/chrome_notification_types.h
+++ b/chrome/browser/chrome_notification_types.h
@@ -340,6 +340,13 @@ enum NotificationType {
   // content::WebContents object, the details are None.
   NOTIFICATION_WEB_CONTENT_SETTINGS_CHANGED,
 
+  // Sidebar -----------------------------------------------------------------

[Devlin, 2015/05/27 16:51:05]

We're working "hard" (read: we really want to, but bandwidth is hard to come by)
to deprecate notifications, so it'd be best to avoid adding any more, if we can.

+
+  // Sent when the sidebar state is changed.
+  // The source is a SidebarManager instance, the details are the changed
+  // SidebarContainer object.
+  NOTIFICATION_SIDEBAR_CHANGED,
+
   // Sync --------------------------------------------------------------------
 
   // The sync service has finished the datatype configuration process. The