Watchdog - Added a JOINABLE state to avoid StartupTimebomb

chrome/browser/metrics/thread_watcher.h

Index: chrome/browser/metrics/thread_watcher.h
===================================================================
--- chrome/browser/metrics/thread_watcher.h	(revision 117912)
+++ chrome/browser/metrics/thread_watcher.h	(working copy)
@@ -514,6 +514,10 @@
   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();
+
   // The singleton of this class.
   static StartupTimeBomb* g_startup_timebomb_;