GTTF: instantiate ThreadChecker early in the test launcher

base/test/parallel_test_launcher.h

 // Copyright 2013 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.
 
 #ifndef BASE_TEST_PARALLEL_TEST_LAUNCHER_H_
 #define BASE_TEST_PARALLEL_TEST_LAUNCHER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 62 matching lines @@
       size_t sequence_number,
       const LaunchChildGTestProcessCallback& callback,
       int exit_code,
       const TimeDelta& elapsed_time,
       bool was_timeout,
       const std::string& output);
 
   // Called by the delay timer when no output was made for a while.
   void OnOutputTimeout();
 
+  // Make sure we don't accidentally call the wrong methods e.g. on the worker
+  // pool thread. With lots of callbacks used this is non-trivial.
+  // Should be the first member so that it's destroyed last: when destroying
+  // other members, especially the worker pool, we may check the code is running
+  // on the correct thread.
+  ThreadChecker thread_checker_;
+
   // Watchdog timer to make sure we do not go without output for too long.
   DelayTimer<ParallelTestLauncher> timer_;
 
   // Monotonically increasing sequence number to uniquely identify each
   // launched child process.
   size_t launch_sequence_number_;
 
   // Map of currently running child processes, keyed by the sequence number.
   typedef std::map<size_t, CommandLine> RunningProcessesMap;
   RunningProcessesMap running_processes_map_;
 
   // Worker pool used to launch processes in parallel.
   scoped_ptr<SequencedWorkerPoolOwner> worker_pool_owner_;
 
-  // Make sure we don't accidentally call the wrong methods e.g. on the worker
-  // pool thread. With lots of callbacks used this is non-trivial.
-  ThreadChecker thread_checker_;
-
   DISALLOW_COPY_AND_ASSIGN(ParallelTestLauncher);
 };
 
 }  // namespace base
 
 #endif  // BASE_TEST_PARALLEL_TEST_LAUNCHER_H_