Check the mime type of cross-origin CSS fetched via the Service Worker.

third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/fetch-request-css-cross-origin-mime-check-worker.js

Index: third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/fetch-request-css-cross-origin-mime-check-worker.js
diff --git a/third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/fetch-request-css-cross-origin-mime-check-worker.js b/third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/fetch-request-css-cross-origin-mime-check-worker.js
new file mode 100644
index 0000000000000000000000000000000000000000..96c1447574934e9a28dabd7bf4b904689722229a
--- /dev/null
+++ b/third_party/WebKit/LayoutTests/http/tests/serviceworker/resources/fetch-request-css-cross-origin-mime-check-worker.js
@@ -0,0 +1,20 @@
+importScripts('../../resources/get-host-info.js');
+importScripts('test-helpers.js');
+
+self.addEventListener('fetch', function(event) {
+    if (event.request.url.indexOf('cross-origin-css.css') != -1) {
+      event.respondWith(fetch(
+          get_host_info()['HTTP_REMOTE_ORIGIN'] + base_path() +
+          'fetch-request-css-cross-origin-mime-check-cross.css',
+          {mode: 'no-cors'}));
+    } else if (event.request.url.indexOf('cross-origin-html.css') != -1) {
+      event.respondWith(fetch(
+          get_host_info()['HTTP_REMOTE_ORIGIN'] + base_path() +
+          'fetch-request-css-cross-origin-mime-check-cross.html',
+          {mode: 'no-cors'}));
+    } else if (event.request.url.indexOf('synthetic.css') != -1) {
+      event.respondWith(new Response("#synthetic { color: blue; }"));
+    } else {
+      event.respondWith(fetch(event.request));
+    }
+  });