Move enable_app_list to a buildflag.

chrome/browser/shell_integration_linux.h

Index: chrome/browser/shell_integration_linux.h
diff --git a/chrome/browser/shell_integration_linux.h b/chrome/browser/shell_integration_linux.h
index cd2ca8ecb8cb5d403b4c7336ded976be0bd794bd..0f44c017c2c2643ae47cd1e2f48a83c668b687d9 100644
--- a/chrome/browser/shell_integration_linux.h
+++ b/chrome/browser/shell_integration_linux.h
@@ -9,6 +9,7 @@
 
 #include "base/files/file_path.h"
 #include "chrome/browser/web_applications/web_app.h"
+#include "chrome/common/features.h"
 #include "url/gurl.h"
 
 namespace base {
@@ -120,7 +121,7 @@ bool CreateDesktopShortcut(
     const web_app::ShortcutInfo& shortcut_info,
     const web_app::ShortcutLocations& creation_locations);
 
-#if defined(ENABLE_APP_LIST)
+#if BUILDFLAG(ENABLE_APP_LIST)
 // Create shortcuts in the application menu for the app launcher. Duplicate
 // shortcuts are avoided, so if a requested shortcut already exists it is
 // deleted first. Also creates the icon required by the shortcut.