Cleanup: Only include background_mode_manager.h when ENABLE_BACKGROUND is defined.

chrome/browser/prefs/browser_prefs.cc

Index: chrome/browser/prefs/browser_prefs.cc
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index d7da2fa4b9d3afa00009d9183a4a4d04e553bfd5..f63d27ab88d665e4a5e242afc39557dc21bd4b18 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -13,10 +13,7 @@
 #include "base/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/about_flags.h"
 #include "chrome/browser/accessibility/invert_bubble_prefs.h"
-#include "chrome/browser/apps/drive/drive_app_mapping.h"
-#include "chrome/browser/apps/shortcut_manager.h"
 #include "chrome/browser/autocomplete/zero_suggest_provider.h"
-#include "chrome/browser/background/background_mode_manager.h"
 #include "chrome/browser/browser_process_impl.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/chrome_content_browser_client.h"
@@ -105,6 +102,10 @@
 #include "chrome/browser/ui/autofill/autofill_dialog_controller.h"
 #endif
 
+#if defined(ENABLE_BACKGROUND)
+#include "chrome/browser/background/background_mode_manager.h"
+#endif
+
 #if defined(ENABLE_CONFIGURATION_POLICY)
 #include "components/policy/core/browser/browser_policy_connector.h"
 #include "components/policy/core/browser/url_blacklist_manager.h"
@@ -112,6 +113,8 @@
 #endif
 
 #if defined(ENABLE_EXTENSIONS)
+#include "chrome/browser/apps/drive/drive_app_mapping.h"
+#include "chrome/browser/apps/shortcut_manager.h"
 #include "chrome/browser/extensions/activity_log/activity_log.h"
 #include "chrome/browser/extensions/api/commands/command_service.h"
 #include "chrome/browser/extensions/api/tabs/tabs_api.h"