Move Thread Name Mapping into ThreadFunc.

base/threading/simple_thread.cc

Index: base/threading/simple_thread.cc
diff --git a/base/threading/simple_thread.cc b/base/threading/simple_thread.cc
index 028d4f4ab23e2cf1ed971d50f2ac6c26fdca0036..4f82c883209e3a463802768399da9d13141e0b55 100644
--- a/base/threading/simple_thread.cc
+++ b/base/threading/simple_thread.cc
@@ -7,6 +7,7 @@
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/threading/platform_thread.h"
+#include "base/threading/thread_id_name_manager.h"
 #include "base/threading/thread_restrictions.h"
 
 namespace base {
@@ -39,6 +40,7 @@ void SimpleThread::Join() {
   DCHECK(HasBeenStarted()) << "Tried to Join a never-started thread.";
   DCHECK(!HasBeenJoined()) << "Tried to Join a thread multiple times.";
   PlatformThread::Join(thread_);
+  ThreadIdNameManager::GetInstance()->RemoveName(&thread_, tid_);

[jar (doing other things), 2013/05/22 19:37:56]

This still scares me a bit if I'm worried about races.  This will run after an
arbitrary amount of time has passed since the thread has gone away.... which
means some other thread may have started, and gotten the previous one's id.

[dsinclair, 2013/05/22 20:22:31]

The ThreadIdNameManager code takes care of this. We remove the thread -> name
pointer which will only be referenced by us. We then only remove the id ->
thread map entry if thread is equal to the provided thread. 

This way, if another thread has come along, it will change id->thread and we'll
leave it, but we'll still clean up our thread->name mapping.

   joined_ = true;
 }