Avoid disk accesses on the wrong thread in URLRequestFileJob

net/url_request/url_request_unittest.cc

Index: net/url_request/url_request_unittest.cc
===================================================================
--- net/url_request/url_request_unittest.cc	(revision 145483)
+++ net/url_request/url_request_unittest.cc	(working copy)
@@ -2454,6 +2454,24 @@
   }
 }
 
+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]);