Avoid disk accesses on the wrong thread in URLRequestFileJob

net/url_request/url_request_unittest.cc

 // Copyright (c) 2012 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 "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shlobj.h>
 #endif
@@ skipping 2436 matching lines @@
 
     EXPECT_TRUE(!r.is_pending());
     EXPECT_EQ(1, d.response_started_count());
     EXPECT_FALSE(d.received_data_before_response());
     EXPECT_EQ(d.bytes_received(), static_cast<int>(file_size));
     EXPECT_EQ("", r.GetSocketAddress().host());
     EXPECT_EQ(0, r.GetSocketAddress().port());
   }
 }
 
+TEST_F(URLRequestTest, FileTest_Cancel) {
+  FilePath app_path;
+  PathService::Get(base::FILE_EXE, &app_path);
+  GURL app_url = FilePathToFileURL(app_path);
+
+  TestDelegate d;
+  {
+    URLRequest r(app_url, &d, &default_context_);
+
+    r.Start();
+    EXPECT_TRUE(r.is_pending());
+    r.Cancel();
+  }
+  // Async cancelation should be safe even when URLRequest has been already
+  // destroyed.
+  MessageLoop::current()->RunAllPending();
+}
+
 TEST_F(URLRequestTest, FileTestFullSpecifiedRange) {
   const size_t buffer_size = 4000;
   scoped_array<char> buffer(new char[buffer_size]);
   FillBuffer(buffer.get(), buffer_size);
 
   FilePath temp_path;
   EXPECT_TRUE(file_util::CreateTemporaryFile(&temp_path));
   GURL temp_url = FilePathToFileURL(temp_path);
   EXPECT_TRUE(file_util::WriteFile(temp_path, buffer.get(), buffer_size));
 
@@ skipping 2171 matching lines @@
   req.SetExtraRequestHeaders(headers);
   req.Start();
   MessageLoop::current()->Run();
   // If the net tests are being run with ChromeFrame then we need to allow for
   // the 'chromeframe' suffix which is added to the user agent before the
   // closing parentheses.
   EXPECT_TRUE(StartsWithASCII(d.data_received(), "Lynx (textmode", true));
 }
 
 }  // namespace net