build: [gn win] fix path names in js2asar

build/asar.gni

@@ -16,6 +16,7 @@ template("chdir_action") {
                            ])
     assert(defined(cwd), "Need cwd in $target_name")
     script = "//electron/build/run-in-dir.py"
+    sources += [ invoker.script ]
     args = [
       cwd,
       rebase_path(invoker.script),

tools/js2asar.py

@@ -26,7 +26,7 @@ def copy_files(source_files, output_dir, folder_name):
     output_path = os.path.join(output_dir, source_file)
     # Files that aren't in the default_app folder need to be put inside
     # the temp one we are making so they end up in the ASAR
-    if not source_file.startswith(folder_name + os.sep):
+    if not os.path.normpath(source_file).startswith(folder_name + os.sep):
       output_path = os.path.join(output_dir, folder_name, source_file)
     safe_mkdir(os.path.dirname(output_path))
     shutil.copy2(source_file, output_path)