Use Referrer-Policy headers for CSS stylesheets

third_party/WebKit/LayoutTests/external/wpt/referrer-policy/generic/subresource/subresource.py

Index: third_party/WebKit/LayoutTests/external/wpt/referrer-policy/generic/subresource/subresource.py
diff --git a/third_party/WebKit/LayoutTests/external/wpt/referrer-policy/generic/subresource/subresource.py b/third_party/WebKit/LayoutTests/external/wpt/referrer-policy/generic/subresource/subresource.py
index 7571b32d0fa758919790dbb2f0abc9a2925e4b75..9ba839a133d96d7373a707aa9c71e01b1569297e 100644
--- a/third_party/WebKit/LayoutTests/external/wpt/referrer-policy/generic/subresource/subresource.py
+++ b/third_party/WebKit/LayoutTests/external/wpt/referrer-policy/generic/subresource/subresource.py
@@ -72,7 +72,8 @@ def respond(request,
             content_type = "text/html",
             payload_generator = __noop,
             cache_control = "no-cache; must-revalidate",
-            access_control_allow_origin = "*"):
+            access_control_allow_origin = "*",
+            maybe_additional_headers = None):
     if preprocess_redirection(request, response):
         return
 
@@ -84,6 +85,11 @@ def respond(request,
                                      access_control_allow_origin)
     response.writer.write_header("content-type", content_type)
     response.writer.write_header("cache-control", cache_control)
+
+    additional_headers = maybe_additional_headers or {}
+    for header, value in additional_headers.items():
+        response.writer.write_header(header, value)
+
     response.writer.end_headers()
 
     server_data = {"headers": json.dumps(request.headers, indent = 4)}