Sync XHR on Worker should not crash when response arrives immediately

third_party/WebKit/Source/core/loader/ThreadableLoaderTest.cpp

 // 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 "core/loader/ThreadableLoader.h"
 
 #include "core/dom/CrossThreadTask.h"
 #include "core/fetch/MemoryCache.h"
 #include "core/fetch/ResourceLoaderOptions.h"
 #include "core/loader/DocumentThreadableLoader.h"
@@ skipping 835 matching lines @@
     callCheckpoint(1);
 
     EXPECT_CALL(checkpoint(), Call(2));
     EXPECT_CALL(*client(), didFailRedirectCheck()).WillOnce(InvokeWithoutArgs(this, &ThreadableLoaderTest::clearLoader));
 
     startLoader(redirectLoopURL());
     callCheckpoint(2);
     serveRequests();
 }
 
+// This test case checks blink doesn't crash even when the response arrives
+// synchronously.
+TEST_P(ThreadableLoaderTest, GetResponseSynchronously)
+{
+    InSequence s;
+    EXPECT_CALL(checkpoint(), Call(1));
+    createLoader(UseAccessControl);
+    callCheckpoint(1);
+
+    EXPECT_CALL(*client(), didFailAccessControlCheck(_));
+    EXPECT_CALL(checkpoint(), Call(2));
+
+    // Currently didFailAccessControlCheck is dispatched synchronously. This
+    // test is not saying that didFailAccessControlCheck should be dispatched
+    // synchronously, but is saying that even when a response is served
+    // synchronously it should not lead to a crash.
+    startLoader(KURL(KURL(), "about:blank"));
+    callCheckpoint(2);
+}
+
 } // namespace
 
 } // namespace blink