Oilpan: handle thread-local weak tracing slightly better.

Source/platform/heap/StackFrameDepth.cpp

 // Copyright 2015 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 "config.h"
 #include "platform/heap/StackFrameDepth.h"
 
 #include "public/platform/Platform.h"
 
 #if OS(WIN)
 #include <stddef.h>
 #include <windows.h>
 #include <winnt.h>
 #elif defined(__GLIBC__)
 extern "C" void* __libc_stack_end;  // NOLINT
 #endif
 
 namespace blink {
 
 static const char* s_avoidOptimization = nullptr;
 
 uintptr_t StackFrameDepth::s_stackFrameLimit = 0;
+#if ENABLE(ASSERT)
+bool StackFrameDepth::s_isEnabled = false;
+#endif
 
 // NEVER_INLINE ensures that |dummy| array on configureLimit() is not optimized away,
 // and the stack frame base register is adjusted |kSafeStackFrameSize|.
 NEVER_INLINE static uintptr_t currentStackFrameBaseOnCallee(const char* dummy)
 {
     s_avoidOptimization = dummy;
     return StackFrameDepth::currentStackFrame();
 }
 
-void StackFrameDepth::configureStackLimit()
+void StackFrameDepth::enableStackLimit()
 {
+#if ENABLE(ASSERT)
+    s_isEnabled = true;
+#endif
+
     static const int kStackRoomSize = 1024;
 
     size_t stackSize = getUnderestimatedStackSize();
     if (stackSize) {
         size_t stackBase = reinterpret_cast<size_t>(getStackStart());
         s_stackFrameLimit = stackBase - stackSize + kStackRoomSize;
         return;
     }
 
     // Fallback version
@@ skipping 103 matching lines @@
     return reinterpret_cast<void*>(__readgsqword(offsetof(NT_TIB64, StackBase)));
 #else
     return reinterpret_cast<void*>(__readfsdword(offsetof(NT_TIB, StackBase)));
 #endif
 #else
 #error Unsupported getStackStart on this platform.
 #endif
 }
 
 } // namespace blink