Make BackgroundContentsService start up BackgroundContents with a delay, as for ExtensionHosts.

chrome/browser/background/background_contents.cc

 // Copyright (c) 2012 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/background/background_contents.h"
 
+#include "base/lazy_instance.h"

[Devlin, 2015/02/20 00:07:57]

don't need

[Yoyo Zhou, 2015/02/20 20:00:01]

Done - also removed from extension_host.cc.

 #include "chrome/browser/background/background_contents_service.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/chrome_extension_web_contents_observer.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/renderer_preferences_util.h"
 #include "chrome/browser/ui/webui/chrome_web_ui_controller_factory.h"
 #include "chrome/common/url_constants.h"
 #include "content/public/browser/notification_service.h"
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/session_storage_namespace.h"
 #include "content/public/browser/site_instance.h"
 #include "content/public/browser/web_contents.h"
+#include "extensions/browser/extension_host_delegate.h"
+#include "extensions/browser/extension_host_queue.h"
+#include "extensions/browser/extensions_browser_client.h"
+#include "extensions/browser/serial_extension_host_queue.h"

[Devlin, 2015/02/20 00:07:57]

don't need

 #include "extensions/browser/view_type_utils.h"
 #include "ui/gfx/geometry/rect.h"
 
 using content::SiteInstance;
 using content::WebContents;
 
 BackgroundContents::BackgroundContents(
     SiteInstance* site_instance,
     int routing_id,
     int main_frame_routing_id,
     Delegate* delegate,
     const std::string& partition_id,
     content::SessionStorageNamespace* session_storage_namespace)
-    : delegate_(delegate) {
+    : delegate_(delegate),
+      extension_host_delegate_(extensions::ExtensionsBrowserClient::Get()
+                                   ->CreateExtensionHostDelegate()) {
   profile_ = Profile::FromBrowserContext(
       site_instance->GetBrowserContext());
 
   WebContents::CreateParams create_params(profile_, site_instance);
   create_params.routing_id = routing_id;
   create_params.main_frame_routing_id = main_frame_routing_id;
   if (session_storage_namespace) {
     content::SessionStorageNamespaceMap session_storage_namespace_map;
     session_storage_namespace_map.insert(
         std::make_pair(partition_id, session_storage_namespace));
@@ skipping 32 matching lines @@
 
   // Unregister for any notifications before notifying observers that we are
   // going away - this prevents any re-entrancy due to chained notifications
   // (http://crbug.com/237781).
   registrar_.RemoveAll();
 
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_BACKGROUND_CONTENTS_DELETED,
       content::Source<Profile>(profile_),
       content::Details<BackgroundContents>(this));
+
+  extension_host_delegate_->GetExtensionHostQueue()->Remove(this);
 }
 
 const GURL& BackgroundContents::GetURL() const {
   return web_contents_.get() ? web_contents_->GetURL() : GURL::EmptyGURL();
 }
 
+void BackgroundContents::CreateRenderViewSoon(const GURL& url) {
+  initial_url_ = url;
+  extension_host_delegate_->GetExtensionHostQueue()->Add(this);
+}
+
 void BackgroundContents::CloseContents(WebContents* source) {
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_BACKGROUND_CONTENTS_CLOSED,
       content::Source<Profile>(profile_),
       content::Details<BackgroundContents>(this));
   delete this;
 }
 
 bool BackgroundContents::ShouldSuppressDialogs(WebContents* source) {
   return true;
@@ skipping 52 matching lines @@
     case chrome::NOTIFICATION_PROFILE_DESTROYED:
     case chrome::NOTIFICATION_APP_TERMINATING: {
       delete this;
       break;
     }
     default:
       NOTREACHED() << "Unexpected notification sent.";
       break;
   }
 }
+
+void BackgroundContents::CreateRenderViewNow() {
+  web_contents()->GetController().LoadURL(initial_url_, content::Referrer(),
+                                          ui::PAGE_TRANSITION_LINK,
+                                          std::string());
+}