Avoid all unnecessary calls to TLS during thread teardown

Mac base_unittests is still flaky....

Pthread is still sometimes crashing Mac on shutdown.

I'm suspicious that my handlers are tickling it.
This removes a DCHECK(), which checked status in
TLS during the teardown.

TBR=rtenneti
Review URL: http://codereview.chromium.org/8424013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@107944 0039d316-1c4b-4281-b951-d872f2087c98

base/tracked_objects.cc

@@ -203,7 +203,6 @@ ThreadData* ThreadData::Get() {
 void ThreadData::OnThreadTermination(void* thread_data) {
   if (!kTrackAllTaskObjects)
     return;  // Not compiled in.
-  DCHECK(tls_index_.initialized());
   if (!thread_data)
     return;
   reinterpret_cast<ThreadData*>(thread_data)->OnThreadTerminationCleanup();