Fix typo in recursion detection logic...

tools/memory_watcher/call_stack.h

 // Copyright (c) 2006-2008 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.
 //
 // Parts of this module come from:
 //  http://www.codeproject.com/KB/applications/visualleakdetector.aspx
 //       by Dan Moulding.
 //  http://www.codeproject.com/KB/threads/StackWalker.aspx
 //       by Jochen Kalmbach
 
@@ skipping 66 matching lines @@
   // Dynamically load the DbgHelp library and supporting routines that we
   // will use.
   static bool LoadDbgHelp();
 
   static void LockDbgHelp() {
     dbghelp_lock_.Acquire();
     active_thread_id_ = GetCurrentThreadId();
   }
 
   static void UnlockDbgHelp() {
-    active_thread_id_ = GetCurrentThreadId();
+    active_thread_id_ = 0;
     dbghelp_lock_.Release();
   }
 
   class AutoDbgHelpLock {
   public:
     AutoDbgHelpLock() {
       CallStack::LockDbgHelp();
     }
     ~AutoDbgHelpLock() {
       CallStack::UnlockDbgHelp();
@@ skipping 61 matching lines @@
  private:
   AllocationStack* next_;     // Pointer used when on the freelist.
   int32 size_;                // Size of block allocated.
   static AllocationStack* freelist_;
   static Lock freelist_lock_;
 
   DISALLOW_EVIL_CONSTRUCTORS(AllocationStack);
 };
 
 #endif  // MEMORY_WATCHER_CALL_STACK_H_