[Prerender] Restore request priorities when swapped in

chrome/browser/prerender/prerender_test_utils.h

Index: chrome/browser/prerender/prerender_test_utils.h
diff --git a/chrome/browser/prerender/prerender_test_utils.h b/chrome/browser/prerender/prerender_test_utils.h
index 40da70aa063f7f1045412b96a3bb06b1613de160..a81897abfa000bebe6e9fb3393d2bb8de70d9080 100644
--- a/chrome/browser/prerender/prerender_test_utils.h
+++ b/chrome/browser/prerender/prerender_test_utils.h
@@ -427,10 +427,12 @@ void InterceptRequestAndCount(
 void CreateMockInterceptorOnIO(const GURL& url, const base::FilePath& file);
 
 // Makes |url| never respond on the first load, and then with the contents of
-// |file| afterwards. When the first load has been scheduled, runs |callback| on
-// the UI thread.
-void CreateHangingFirstRequestInterceptorOnIO(
-    const GURL& url, const base::FilePath& file, base::Closure callback);
+// |file| afterwards. When the first load has been scheduled, runs |callback_io|
+// on the IO thread.
+void CreateHangingFirstRequestInterceptor(
+    const GURL& url,
+    const base::FilePath& file,
+    base::Callback<void(net::URLRequest*)> callback_io);
 
 }  // namespace test_utils