Revert "Track thread activities in order to diagnose hangs."

base/synchronization/lock_impl_posix.cc

Index: base/synchronization/lock_impl_posix.cc
diff --git a/base/synchronization/lock_impl_posix.cc b/base/synchronization/lock_impl_posix.cc
index e54595b87f10a353647d4a0ee40aa30d2a649780..7024ab2b2190aeef8c214508e33906da2f6de4fe 100644
--- a/base/synchronization/lock_impl_posix.cc
+++ b/base/synchronization/lock_impl_posix.cc
@@ -7,7 +7,6 @@
 #include <errno.h>
 #include <string.h>
 
-#include "base/debug/activity_tracker.h"
 #include "base/logging.h"
 #include "base/synchronization/lock.h"
 
@@ -60,7 +59,6 @@ bool LockImpl::Try() {
 }
 
 void LockImpl::Lock() {
-  base::debug::ScopedLockAcquireActivity lock_activity(this);
   int rv = pthread_mutex_lock(&native_handle_);
   DCHECK_EQ(rv, 0) << ". " << strerror(rv);
 }