Add unit test to check for broker FD leak

sandbox/linux/tests/unit_tests.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 <fcntl.h>
 #include <poll.h>
 #include <signal.h>
 #include <stdio.h>
 #include <sys/resource.h>
 #include <sys/time.h>
@@ skipping 190 matching lines @@
   std::string details(TestFailedMessage(msg));
 
   bool subprocess_terminated_normally = WIFEXITED(status);
   ASSERT_TRUE(subprocess_terminated_normally) << details;
   int subprocess_exit_status = WEXITSTATUS(status);
   ASSERT_EQ(kExpectedValue, subprocess_exit_status) << details;
   bool subprocess_exited_but_printed_messages = !msg.empty();
   EXPECT_FALSE(subprocess_exited_but_printed_messages) << details;
 }
 
+void UnitTests::DeathSuccessAllowNoise(int status,
+                                       const std::string& msg,
+                                       const void*) {
+  std::string details(TestFailedMessage(msg));
+
+  bool subprocess_terminated_normally = WIFEXITED(status);
+  ASSERT_TRUE(subprocess_terminated_normally) << details;
+  int subprocess_exit_status = WEXITSTATUS(status);
+  ASSERT_EQ(kExpectedValue, subprocess_exit_status) << details;
+}
+
 void UnitTests::DeathMessage(int status,
                              const std::string& msg,
                              const void* aux) {
   std::string details(TestFailedMessage(msg));
   const char* expected_msg = static_cast<const char*>(aux);
 
   bool subprocess_terminated_normally = WIFEXITED(status);
   ASSERT_TRUE(subprocess_terminated_normally) << details;
   int subprocess_exit_status = WEXITSTATUS(status);
   ASSERT_EQ(kExitWithAssertionFailure, subprocess_exit_status) << details;
@@ skipping 31 matching lines @@
   fflush(stderr);
   _exit(kExitWithAssertionFailure);
 }
 
 void UnitTests::IgnoreThisTest() {
   fflush(stderr);
   _exit(kIgnoreThisTest);
 }
 
 }  // namespace