[Mac] Support for Touch Bar Customization

chrome/browser/app_controller_mac.mm

Index: chrome/browser/app_controller_mac.mm
diff --git a/chrome/browser/app_controller_mac.mm b/chrome/browser/app_controller_mac.mm
index 78d27e24bfe65d7ece00191b85791a9638cee468..f6e6ec5789882d8e481490891267886b5720e671 100644
--- a/chrome/browser/app_controller_mac.mm
+++ b/chrome/browser/app_controller_mac.mm
@@ -741,6 +741,12 @@ class AppControllerProfileObserver : public ProfileAttributesStorage::Observer {
 
   handoff_active_url_observer_bridge_.reset(
       new HandoffActiveURLObserverBridge(self));
+
+  NSApplication* application = [NSApplication sharedApplication];
+  if ([application respondsToSelector:
+      @selector(setAutomaticCustomizeTouchBarMenuItemEnabled:)]) {
+    [application setAutomaticCustomizeTouchBarMenuItemEnabled:YES];
+  }
 }
 
 // Helper function for populating and displaying the in progress downloads at