Fix recursion bug in blocking a fetch and add a test

headless/public/util/generic_url_request_job_test.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "headless/public/util/generic_url_request_job.h"
 
 #include <memory>
 #include <string>
 #include <vector>
 
@@ skipping 325 matching lines @@
       "{\"url\": \"https://example.com/\","
       " \"headers\": {"
       "   \"Cookie\": \"basic_cookie=1; secure_cookie=2; http_only_cookie=3\","
       "   \"Referer\": \"\""
       " }"
       "}";
 
   EXPECT_THAT(fetch_request_, MatchesJson(expected_request_json));
 }
 
+TEST_F(GenericURLRequestJobTest, DelegateBlocksLoading) {
+  std::string reply =
+      "{\"url\":\"https://example.com\","
+      " \"http_response_code\":200,"
+      " \"data\":\"Reply\","
+      " \"headers\":{\"Content-Type\":\"text/html; charset=UTF-8\"}}";
+
+  job_delegate_.SetShouldBlock(true);
+
+  std::unique_ptr<net::URLRequest> request(
+      CreateAndCompleteJob(GURL("https://example.com"), reply));
+
+  EXPECT_EQ(net::URLRequestStatus::FAILED, request->status().status());
+  EXPECT_EQ(net::ERR_FILE_NOT_FOUND, request->status().error());
+}
+
 }  // namespace headless