Load ash_sysui resources with ResourceLoader.

components/mus/BUILD.gn

Index: components/mus/BUILD.gn
diff --git a/components/mus/BUILD.gn b/components/mus/BUILD.gn
index c9e3737f2effc8164bdd1c12455578c18870b945..fb42e4ae52dc1958d1662bae4cca7ea7e4638fdb 100644
--- a/components/mus/BUILD.gn
+++ b/components/mus/BUILD.gn
@@ -118,11 +118,13 @@ source_set("lib") {
   }
 }
 
+resource_out_dir = "$root_out_dir/$mojo_application_subdir/mus/resources"
+
 repack("resources_strings") {
   sources = [
     "$root_gen_dir/ui/strings/app_locale_settings_en-US.pak",
   ]
-  output = "$root_out_dir/$mojo_application_subdir/mus/resources/mus_app_resources_strings.pak"
+  output = "$resource_out_dir/mus_app_resources_strings.pak"
   deps = [
     "//ui/strings",
   ]
@@ -132,7 +134,7 @@ repack("resources_100") {
   sources = [
     "$root_gen_dir/ui/resources/ui_resources_100_percent.pak",
   ]
-  output = "$root_out_dir/$mojo_application_subdir/mus/resources/mus_app_resources_100.pak"
+  output = "$resource_out_dir/mus_app_resources_100.pak"
   deps = [
     "//ui/resources",
   ]
@@ -142,7 +144,7 @@ repack("resources_200") {
   sources = [
     "$root_gen_dir/ui/resources/ui_resources_200_percent.pak",
   ]
-  output = "$root_out_dir/$mojo_application_subdir/mus/resources/mus_app_resources_200.pak"
+  output = "$resource_out_dir/mus_app_resources_200.pak"
   deps = [
     "//ui/resources",
   ]