Hide mac background mode prefs ui if background mode is not enabled.

chrome/browser/cocoa/preferences_window_controller.mm

Index: chrome/browser/cocoa/preferences_window_controller.mm
diff --git a/chrome/browser/cocoa/preferences_window_controller.mm b/chrome/browser/cocoa/preferences_window_controller.mm
index c382603ad4adcad75ba94c2cbbd8d90023beb9e4..7c62797454782916356a415ce4befa802bf82650 100644
--- a/chrome/browser/cocoa/preferences_window_controller.mm
+++ b/chrome/browser/cocoa/preferences_window_controller.mm
@@ -534,6 +534,15 @@ class ManagedPrefsBannerState : public ManagedPrefsBannerBase {
   RemoveViewFromView(underTheHoodContentView_, enableLoggingCheckbox_);
 #endif  // !defined(GOOGLE_CHROME_BUILD)
 
+  // If BackgroundMode is not enabled, hide the related prefs UI.
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kEnableBackgroundMode)) {
+    RemoveViewFromView(underTheHoodContentView_, backgroundModeTitle_);
+    RemoveViewFromView(underTheHoodContentView_, backgroundModeCheckbox_);
+    RemoveViewFromView(underTheHoodContentView_, backgroundModeDescription_);
+    RemoveViewFromView(underTheHoodContentView_, backgroundModeLearnMore_);
+  }
+
   // There are four problem children within the groups:
   //   Basics - Default Browser
   //   Personal Stuff - Sync