brave: add support for command line arguments

Add formal argument `commandLineArgs` to the brave derivation and append it
to the `gappsWrapperArgs` expected by the `wrapGAppsHook`. This adds some
flexibility to the wrapper creation of brave, and aligns with customization
avalible in other chromium derivation.

pkgs/applications/networking/browsers/brave/default.nix

@@ -41,6 +41,7 @@
 , zlib
 , xdg-utils
 , wrapGAppsHook
+, commandLineArgs ? ""
 }:
 
 let
@@ -156,6 +157,11 @@ stdenv.mkDerivation rec {
       runHook postInstall
   '';
 
+  preFixup = ''
+    # Add command line args to wrapGApp.
+    gappsWrapperArgs+=(--add-flags ${lib.escapeShellArg commandLineArgs})
+  '';
+
   installCheckPhase = ''
     # Bypass upstream wrapper which suppresses errors
     $out/opt/brave.com/brave/brave --version