Set credentials mode "same-origin" when crossOrigin=anonymous is set.

third_party/WebKit/LayoutTests/http/tests/security/resources/abe-allow-credentials.php

Index: third_party/WebKit/LayoutTests/http/tests/security/resources/abe-allow-credentials.php
diff --git a/third_party/WebKit/LayoutTests/http/tests/security/resources/abe-allow-credentials.php b/third_party/WebKit/LayoutTests/http/tests/security/resources/abe-allow-credentials.php
index 2ca740807aa1f319cae83287a5be62d047151b97..bce72facef2f3b3efa2381541ecebe058a249841 100644
--- a/third_party/WebKit/LayoutTests/http/tests/security/resources/abe-allow-credentials.php
+++ b/third_party/WebKit/LayoutTests/http/tests/security/resources/abe-allow-credentials.php
@@ -1,4 +1,17 @@
 <?php
+$cookie_check = $_GET["Cookie"];
+if (isset($cookie_check)) {
+  if ($cookie_check == "NotSet") {
+    if (isset($_COOKIE['TestCookie'])) {
+      header("HTTP/1.0 404 Not Found");
+      exit;
+    }
+  } else if ($cookie_check != $_COOKIE['TestCookie']) {
+    header("HTTP/1.0 404 Not Found");
+    exit;
+  }
+}
+
 header("Access-Control-Allow-Origin: http://127.0.0.1:8000");
 header("Access-Control-Allow-Credentials: true");