Add "Keep chrome running in background" preference.

chrome/browser/background_mode_manager.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 CHROME_BROWSER_BACKGROUND_MODE_MANAGER_H_
 #define CHROME_BROWSER_BACKGROUND_MODE_MANAGER_H_
 #pragma once
 
 #include "base/gtest_prod_util.h"
 #include "chrome/browser/background_application_list_model.h"
@@ skipping 28 matching lines @@
 // background.
 class BackgroundModeManager
     : public NotificationObserver,
       public ui::SimpleMenuModel::Delegate,
       public BackgroundApplicationListModel::Observer,
       public ProfileKeyedService {
  public:
   BackgroundModeManager(Profile* profile, CommandLine* command_line);
   virtual ~BackgroundModeManager();
 
-  static bool IsBackgroundModeEnabled(const CommandLine* command_line);
   static void RegisterPrefs(PrefService* prefs);
 
  private:
   friend class TestBackgroundModeManager;
   friend class BackgroundModeManagerTest;
   FRIEND_TEST_ALL_PREFIXES(BackgroundModeManagerTest,
                            BackgroundAppLoadUnload);
   FRIEND_TEST_ALL_PREFIXES(BackgroundModeManagerTest,
                            BackgroundAppInstallUninstall);
   FRIEND_TEST_ALL_PREFIXES(BackgroundModeManagerTest,
@@ skipping 79 matching lines @@
   // Create a context menu, or replace/update an existing context menu, for the
   // status tray icon which, among other things, allows the user to shutdown
   // Chrome when running in background mode.
   virtual void UpdateStatusTrayIconContextMenu();
 
   // Returns a browser window, or creates one if none are open. Used by
   // operations (like displaying the preferences dialog) that require a Browser
   // window.
   Browser* GetBrowserWindow();
 
+  // Returns true if the "Let chrome run in the background" pref is checked.
+  bool IsBackgroundModePrefEnabled();
+
+  // Turns off background mode if it's currently enabled.
+  void DisableBackgroundMode();
+
+  // Turns on background mode if it's currently disabled.
+  void EnableBackgroundMode();
+
+  // Returns true if background mode is permanently disabled for this chrome
+  // session.
+  static bool IsBackgroundModePermanentlyDisabled(
+      const CommandLine* command_line);
+
+  // Registrars for managing our change observers.
   NotificationRegistrar registrar_;
+  PrefChangeRegistrar pref_registrar_;
 
   // The parent profile for this object.
   Profile* profile_;
 
   // The cached list of BackgroundApplications.
   BackgroundApplicationListModel applications_;
 
   // The number of background apps currently loaded.
   int background_app_count_;
 
@@ skipping 19 matching lines @@
   // platform doesn't support status icons.
   StatusTray* status_tray_;
 
   // Reference to our status icon (if any) - owned by the StatusTray.
   StatusIcon* status_icon_;
 
   DISALLOW_COPY_AND_ASSIGN(BackgroundModeManager);
 };
 
 #endif  // CHROME_BROWSER_BACKGROUND_MODE_MANAGER_H_