Don't use GetAsTabContents. Send notifications from TabContentsView instead.

chrome/browser/tab_contents/background_contents.cc

 // Copyright (c) 2010 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.
 
 #include "chrome/browser/tab_contents/background_contents.h"
 
 #include "chrome/browser/background_contents_service.h"
 #include "chrome/browser/browsing_instance.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
@@ skipping 191 matching lines @@
 
 void BackgroundContents::ProcessDOMUIMessage(
     const ViewHostMsg_DomMessage_Params& params) {
   // TODO(rafaelw): It may make sense for extensions to be able to open
   // BackgroundContents to chrome-extension://<id> pages. Consider implementing.
   render_view_host_->BlockExtensionRequest(params.request_id);
 }
 
 void BackgroundContents::CreateNewWindow(
     int route_id,
-    WindowContainerType window_container_type,
-    const string16& frame_name) {
+    const ViewHostMsg_CreateWindow_Params& params) {
   delegate_view_helper_.CreateNewWindow(
       route_id,
       render_view_host_->process()->profile(),
       render_view_host_->site_instance(),
       DOMUIFactory::GetDOMUIType(render_view_host_->process()->profile(), url_),
       this,
-      window_container_type,
-      frame_name);
+      params.window_container_type,
+      params.frame_name);
 }
 
 void BackgroundContents::CreateNewWidget(int route_id,
                                          WebKit::WebPopupType popup_type) {
   NOTREACHED();
 }
 
 void BackgroundContents::CreateNewFullscreenWidget(
     int route_id, WebKit::WebPopupType popup_type) {
   NOTREACHED();
@@ skipping 21 matching lines @@
 BackgroundContents*
 BackgroundContents::GetBackgroundContentsByID(int render_process_id,
                                               int render_view_id) {
   RenderViewHost* render_view_host =
       RenderViewHost::FromID(render_process_id, render_view_id);
   if (!render_view_host)
     return NULL;
 
   return render_view_host->delegate()->GetAsBackgroundContents();
 }