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

base/threading/platform_thread_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/threading/platform_thread.h"
 
 #include <stddef.h>
 
-#include "base/debug/activity_tracker.h"
 #include "base/debug/alias.h"
 #include "base/debug/profiler.h"
 #include "base/logging.h"
 #include "base/threading/thread_id_name_manager.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/tracked_objects.h"
 #include "base/win/scoped_handle.h"
 
 namespace base {
 
@@ skipping 184 matching lines @@
 // static
 bool PlatformThread::CreateNonJoinableWithPriority(size_t stack_size,
                                                    Delegate* delegate,
                                                    ThreadPriority priority) {
   return CreateThreadInternal(stack_size, delegate, nullptr /* non-joinable */,
                               priority);
 }
 
 // static
 void PlatformThread::Join(PlatformThreadHandle thread_handle) {
-  // Record the event that this thread is blocking upon (for hang diagnosis).
-  base::debug::ScopedThreadJoinActivity thread_activity(&thread_handle);
-
   DCHECK(thread_handle.platform_handle());
   // TODO(willchan): Enable this check once I can get it to work for Windows
   // shutdown.
   // Joining another thread may block the current thread for a long time, since
   // the thread referred to by |thread_handle| may still be running long-lived /
   // blocking tasks.
 #if 0
   base::ThreadRestrictions::AssertIOAllowed();
 #endif
 
@@ skipping 60 matching lines @@
       return ThreadPriority::REALTIME_AUDIO;
     case THREAD_PRIORITY_ERROR_RETURN:
       DPCHECK(false) << "GetThreadPriority error";  // Falls through.
     default:
       NOTREACHED() << "Unexpected priority: " << priority;
       return ThreadPriority::NORMAL;
   }
 }
 
 }  // namespace base