Use process-per-app-instance for hosted apps without background permission.

content/common/content_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_COMMON_NOTIFICATION_TYPE_H_
 #define CONTENT_COMMON_NOTIFICATION_TYPE_H_
 #pragma once
 
 // This file describes various types used to describe and filter notifications
 // that pass through the NotificationService.
@@ skipping 351 matching lines @@
   // 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,
 
   // 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,
 
+  // Sent from ~SiteInstance.  The source is the SiteInstance, and the details
+  // are unused.
+  NOTIFICATION_SITE_INSTANCE_DELETED,
+
   // 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,
 
   // Notification posted from ExecuteJavascriptInWebFrameNotifyResult. The
   // source is the RenderViewHost ExecuteJavascriptInWebFrameNotifyResult was
   // invoked on. The details are a std::pair<int, Value*> with the int giving
   // the id returned from ExecuteJavascriptInWebFrameNotifyResult and the
@@ skipping 58 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_COMMON_NOTIFICATION_TYPE_H_