Revert "Hack around TLS destructors firing after the process exits"

runtime/vm/os_thread_win.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"  // NOLINT
 #if defined(TARGET_OS_WINDOWS)
 
 #include "vm/growable_array.h"
 #include "vm/os_thread.h"
 
 #include <process.h>  // NOLINT
 
 #include "platform/assert.h"
 
 namespace dart {
 
-// This flag is flipped by platform_win.cc when the process is exiting.
-// TODO(zra): Remove once VM shuts down cleanly.
-bool private_flag_windows_run_tls_destructors = true;
-
 class ThreadStartData {
  public:
   ThreadStartData(OSThread::ThreadStartFunction function, uword parameter)
       : function_(function), parameter_(parameter) {}
 
   OSThread::ThreadStartFunction function() const { return function_; }
   uword parameter() const { return parameter_; }
 
  private:
   OSThread::ThreadStartFunction function_;
@@ skipping 600 matching lines @@
 
 #else  // _WIN64
 
 #pragma comment(linker, "/INCLUDE:__tls_used")
 #pragma comment(linker, "/INCLUDE:_p_thread_callback_dart")
 
 #endif  // _WIN64
 
 // Static callback function to call with each thread termination.
 void NTAPI OnDartThreadExit(PVOID module, DWORD reason, PVOID reserved) {
-  if (!dart::private_flag_windows_run_tls_destructors) {
-    return;
-  }
   // On XP SP0 & SP1, the DLL_PROCESS_ATTACH is never seen. It is sent on SP2+
   // and on W2K and W2K3. So don't assume it is sent.
   if (DLL_THREAD_DETACH == reason || DLL_PROCESS_DETACH == reason) {
     dart::ThreadLocalData::RunDestructors();
     dart::MonitorWaitData::ThreadExit();
   }
 }
 
 // .CRT$XLA to .CRT$XLZ is an array of PIMAGE_TLS_CALLBACK pointers that are
 // called automatically by the OS loader code (not the CRT) when the module is
@@ skipping 30 matching lines @@
 #pragma data_seg(".CRT$XLB")
 PIMAGE_TLS_CALLBACK p_thread_callback_dart = OnDartThreadExit;
 
 // Reset the default section.
 #pragma data_seg()
 
 #endif  // _WIN64
 }  // extern "C"
 
 #endif  // defined(TARGET_OS_WINDOWS)