WTF: Initialize main-thread stack estimates when WTF starts up.

third_party/WebKit/Source/wtf/Threading.h

 /*
  * Copyright (C) 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Justin Haygood (jhaygood@reaktix.com)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 29 matching lines @@
 #if OS(WIN)
 typedef uint32_t ThreadIdentifier;
 #else
 typedef intptr_t ThreadIdentifier;
 #endif
 
 namespace internal {
 WTF_EXPORT ThreadIdentifier currentThreadSyscall();
 }  // namespace internal
 
+// Initializes global state required by |currentThread|.
+// Needs to be called once during program execution, before |currentThread|.
+WTF_EXPORT void initializeCurrentThread();
+
 WTF_EXPORT ThreadIdentifier currentThread();
 
 #if DCHECK_IS_ON()
 WTF_EXPORT bool isBeforeThreadCreated();
 WTF_EXPORT void willCreateThread();
 #endif
 
 }  // namespace WTF
 
 using WTF::ThreadIdentifier;
 using WTF::currentThread;
 
 #endif  // Threading_h