Fix panels being removed from PanelManager prematurely.

content/public/browser/notification_types.h

 // Copyright (c) 2011 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 CONTENT_PUBLIC_BROWSER_NOTIFICATION_TYPE_H_
 #define CONTENT_PUBLIC_BROWSER_NOTIFICATION_TYPE_H_
 #pragma once
 
 // This file describes various types used to describe and filter notifications
 // that pass through the NotificationService.
@@ skipping 333 matching lines @@
   // is the RenderViewHost sending the message, and no details are provided.
   // Note:  This message is not sent in response to RenderView closure
   // initiated by window.close().
   NOTIFICATION_RENDER_VIEW_HOST_WILL_CLOSE_RENDER_VIEW,
 
   // This notifies the observer that the drag operation ack in a drag and
   // drop operation was received. The source is the RenderViewHost.
   // Note: Used only in testing.
   NOTIFICATION_RENDER_VIEW_HOST_DID_RECEIVE_DRAG_TARGET_DROP_ACK,
 
+  // Sent from RenderViewHost::OnMsgShouldCloseACK. This means handling
+  // ViewMsg_ShouldClose has been completed and result received.
+  NOTIFICATION_RENDER_VIEW_HOST_RECEIVED_ON_MSG_SHOULD_CLOSE_ACK,

[jam, 2011/11/11 21:19:19]

notifications, in general, are a hacky way of getting some code to call another
part of code. in this case, it might be used by a test only, but then later
others might use it as well and refactoring that code which sends it becomes
complicated.

are there are no other existing notifications or callbacks that you can reuse
here?

+
   // Indicates a RenderWidgetHost has been hidden or restored. The source is
   // the RWH whose visibility changed, the details is a bool set to true if
   // the new state is "visible."
   NOTIFICATION_RENDER_WIDGET_VISIBILITY_CHANGED,
 
   // The focused element inside a page has changed.  The source is the
   // TabContents containing the render view host for the page. The details is
   // a Details<const bool> that indicates whether or not an editable node was
   // focused.
   NOTIFICATION_FOCUS_CHANGED_IN_PAGE,
@@ skipping 73 matching lines @@
   // of a temporary zoom level change, the details is an empty string.
   NOTIFICATION_ZOOM_LEVEL_CHANGED,
 
   // Custom notifications used by the embedder should start from here.
   NOTIFICATION_CONTENT_END,
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_NOTIFICATION_TYPE_H_