Move files in wtf/ to platform/wtf/ (Part 7).

third_party/WebKit/Source/wtf/StackUtil.h

 // Copyright 2017 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.
 
-#ifndef StackUtil_h
-#define StackUtil_h
+#include "platform/wtf/StackUtil.h"
 
-#include "wtf/Compiler.h"
-#include "wtf/WTFExport.h"
-#include "wtf/build_config.h"
-#include <stddef.h>
-#include <stdint.h>
-
-namespace WTF {
-
-WTF_EXPORT size_t getUnderestimatedStackSize();
-WTF_EXPORT void* getStackStart();
-
-namespace internal {
-
-WTF_EXPORT extern uintptr_t s_mainThreadStackStart;
-WTF_EXPORT extern uintptr_t s_mainThreadUnderestimatedStackSize;
-
-WTF_EXPORT void initializeMainThreadStackEstimate();
-
-#if OS(WIN) && COMPILER(MSVC)
-size_t threadStackSize();
-#endif
-
-}  // namespace internal
-
-// Returns true if the function is not called on the main thread. Note carefully
-// that this function may have false positives, i.e. it can return true even if
-// we are on the main thread. If the function returns false, we are certainly
-// on the main thread.
-inline bool mayNotBeMainThread() {
-  uintptr_t dummy;
-  uintptr_t addressDiff =
-      internal::s_mainThreadStackStart - reinterpret_cast<uintptr_t>(&dummy);
-  // This is a fast way to judge if we are in the main thread.
-  // If |&dummy| is within |s_mainThreadUnderestimatedStackSize| byte from
-  // the stack start of the main thread, we judge that we are in
-  // the main thread.
-  return addressDiff >= internal::s_mainThreadUnderestimatedStackSize;
-}
-
-}  // namespace WTF
-
-#endif  // StackUtil_h
+// The contents of this header was moved to platform/wtf as part of
+// WTF migration project. See the following post for details:
+// https://groups.google.com/a/chromium.org/d/msg/blink-dev/tLdAZCTlcAA/bYXVT8gYCAAJ