Add a -verbose:thread option.

Change-Id: Ie9bbe2195d7c427379e4a27d3fe51f1a71e58597
diff --git a/src/thread_list.h b/src/thread_list.h
index e83b043..e5d9eab 100644
--- a/src/thread_list.h
+++ b/src/thread_list.h
@@ -28,7 +28,7 @@
   static const uint32_t kInvalidId = 0;
   static const uint32_t kMainId = 1;
 
-  ThreadList();
+  ThreadList(bool verbose);
   ~ThreadList();
 
   void Dump(std::ostream& os);
@@ -60,6 +60,8 @@
   void SuspendAllDaemonThreads();
   void WaitForNonDaemonThreadsToExit();
 
+  bool verbose_;
+
   mutable Mutex thread_list_lock_;
   std::bitset<kMaxThreadId> allocated_ids_;
   std::list<Thread*> list_;