Introduce background.scripts feature for extension manifests.

chrome/browser/extensions/extension_service.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/extensions/extension_service.h"
 
 #include <algorithm>
 #include <set>
 
 #include "base/basictypes.h"
@@ skipping 2456 matching lines @@
   for (ExtensionSet::const_iterator it = extensions_.begin();
        it != extensions_.end(); ++it) {
     if ((*it)->is_app() && (*it)->location() != Extension::COMPONENT)
       result.insert((*it)->id());
   }
 
   return result;
 }
 
 bool ExtensionService::IsBackgroundPageReady(const Extension* extension) {
-  return (extension->background_url().is_empty() ||
+  return (!extension->has_background_page() ||
           extension_runtime_data_[extension->id()].background_page_ready);
 }
 
 void ExtensionService::SetBackgroundPageReady(const Extension* extension) {
-  DCHECK(!extension->background_url().is_empty());
+  DCHECK(extension->has_background_page());
   extension_runtime_data_[extension->id()].background_page_ready = true;
   content::NotificationService::current()->Notify(
       chrome::NOTIFICATION_EXTENSION_BACKGROUND_PAGE_READY,
       content::Source<const Extension>(extension),
       content::NotificationService::NoDetails());
 }
 
 bool ExtensionService::IsBeingUpgraded(const Extension* extension) {
   return extension_runtime_data_[extension->id()].being_upgraded;
 }
@@ skipping 150 matching lines @@
   //
   // To coexist with certain unit tests that don't have an IO thread message
   // loop available at ExtensionService shutdown, we lazy-initialize this
   // object so that those cases neither create nor destroy a SocketController.
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   if (!socket_controller_) {
     socket_controller_ = new extensions::SocketController();
   }
   return socket_controller_;
 }