ThreadWatcher: fix use-after-delete bug.

chrome/browser/metrics/thread_watcher.h

 // 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.
 
 // This file defines a WatchDog thread that monitors the responsiveness of other
 // browser threads like UI, IO, DB, FILE and CACHED threads. It also defines
 // ThreadWatcher class which performs health check on threads that would like to
 // be watched. This file also defines ThreadWatcherList class that has list of
 // all active ThreadWatcher objects.
 //
@@ skipping 608 matching lines @@
   void Arm(const base::TimeDelta& duration);
 
   // Disarms |startup_watchdog_| thread and then deletes it which stops the
   // Watchdog thread.
   void Disarm();
 
   // Disarms |g_startup_timebomb_|.
   static void DisarmStartupTimeBomb();
 
  private:
-  // Deletes |startup_watchdog_| if it is joinable. If |startup_watchdog_| is
-  // not joinable, then it will post a delayed task to try again.
-  void DeleteStartupWatchdog();
+  // Deletes the watchdog thread if it is joinable; otherwise it posts a delayed
+  // task to try again.
+  static void DeleteStartupWatchdog(const base::PlatformThreadId thread_id,
+                                    base::Watchdog* startup_watchdog);
 
   // The singleton of this class.
   static StartupTimeBomb* g_startup_timebomb_;
 
   // Watches for hangs during startup until it is disarm'ed.
   base::Watchdog* startup_watchdog_;
 
   // The |thread_id_| on which this object is constructed.
   const base::PlatformThreadId thread_id_;
 
@@ skipping 45 matching lines @@
   // shutdown_watchdog_ watches for hangs during shutdown.
   base::Watchdog* shutdown_watchdog_;
 
   // The |thread_id_| on which this object is constructed.
   const base::PlatformThreadId thread_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ShutdownWatcherHelper);
 };
 
 #endif  // CHROME_BROWSER_METRICS_THREAD_WATCHER_H_