This CL is due the thread I have made on chromium-dev:...

base/scoped_ptr.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.
 
 // Scopers help you manage ownership of a pointer, helping you easily manage the
 // a pointer within a scope, and automatically destroying the pointer at the
 // end of a scope.  There are two main classes you will use, which coorespond
 // to the operators new/delete and new[]/delete[].
 //
 // Example usage (scoped_ptr):
@@ skipping 18 matching lines @@
 // Example usage (scoped_array):
 //   {
 //     scoped_array<Foo> foo(new Foo[100]);
 //     foo.get()->Method();  // Foo::Method on the 0th element.
 //     foo[10].Method();     // Foo::Method on the 10th element.
 //   }
 
 #ifndef BASE_SCOPED_PTR_H_
 #define BASE_SCOPED_PTR_H_
 
+#include "base/thread_collision_warner.h"
+
 // This is an implementation designed to match the anticipated future TR2
 // implementation of the scoped_ptr class, and its closely-related brethren,
 // scoped_array, scoped_ptr_malloc.
 
 #include <assert.h>
 #include <stdlib.h>
 #include <cstddef>
 
 // A scoped_ptr<T> is like a T*, except that the destructor of scoped_ptr<T>
 // automatically deletes the pointer it holds (if any).
@@ skipping 20 matching lines @@
   // We don't need to test ptr_ == NULL because C++ does that for us.
   ~scoped_ptr() {
     enum { type_must_be_complete = sizeof(C) };
     delete ptr_;
   }
 
   // Reset.  Deletes the current owned object, if any.
   // Then takes ownership of a new object, if given.
   // this->reset(this->get()) works.
   void reset(C* p = NULL) {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
     if (p != ptr_) {
       enum { type_must_be_complete = sizeof(C) };
       delete ptr_;
       ptr_ = p;
     }
   }
 
   // Accessors to get the owned object.
   // operator* and operator-> will assert() if there is no current object.
   C& operator*() const {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
     assert(ptr_ != NULL);
     return *ptr_;
   }
   C* operator->() const  {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
     assert(ptr_ != NULL);
     return ptr_;
   }
-  C* get() const { return ptr_; }
+  C* get() const { 
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
+    return ptr_; 
+  }
 
   // Comparison operators.
   // These return whether two scoped_ptr refer to the same object, not just to
   // two different but equal objects.
-  bool operator==(C* p) const { return ptr_ == p; }
-  bool operator!=(C* p) const { return ptr_ != p; }
+  bool operator==(C* p) const { 
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
+    return ptr_ == p; 
+  }
+  bool operator!=(C* p) const { 
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
+    return ptr_ != p; 
+  }
 
   // Swap two scoped pointers.
   void swap(scoped_ptr& p2) {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
+
     C* tmp = ptr_;
     ptr_ = p2.ptr_;
     p2.ptr_ = tmp;
   }
 
   // Release a pointer.
   // The return value is the current pointer held by this object.
   // If this object holds a NULL pointer, the return value is NULL.
   // After this operation, this object will hold a NULL pointer,
   // and will not own the object any more.
   C* release() {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_);
+
     C* retVal = ptr_;
     ptr_ = NULL;
     return retVal;
   }
 
  private:
   C* ptr_;
 
   // Forbid comparison of scoped_ptr types.  If C2 != C, it totally doesn't
   // make sense, and if C2 == C, it still doesn't make sense because you should
   // never have the same object owned by two different scoped_ptrs.
   template <class C2> bool operator==(scoped_ptr<C2> const& p2) const;
   template <class C2> bool operator!=(scoped_ptr<C2> const& p2) const;
 
   // Disallow evil constructors
   scoped_ptr(const scoped_ptr&);
   void operator=(const scoped_ptr&);
+
+  D_DEFINE_CRITICAL_SECTION(scoped_ptr_);
 };
 
 // Free functions
 template <class C>
 void swap(scoped_ptr<C>& p1, scoped_ptr<C>& p2) {
   p1.swap(p2);
 }
 
 template <class C>
 bool operator==(C* p1, const scoped_ptr<C>& p2) {
@@ skipping 30 matching lines @@
   // We don't need to test ptr_ == NULL because C++ does that for us.
   ~scoped_array() {
     enum { type_must_be_complete = sizeof(C) };
     delete[] array_;
   }
 
   // Reset.  Deletes the current owned object, if any.
   // Then takes ownership of a new object, if given.
   // this->reset(this->get()) works.
   void reset(C* p = NULL) {
+    D_BOOK_CRITICAL_SECTION(scoped_array_);
     if (p != array_) {
       enum { type_must_be_complete = sizeof(C) };
       delete[] array_;
       array_ = p;
     }
   }
 
   // Get one element of the current object.
   // Will assert() if there is no current object, or index i is negative.
   C& operator[](std::ptrdiff_t i) const {
+    D_BOOK_CRITICAL_SECTION(scoped_array_);
     assert(i >= 0);
     assert(array_ != NULL);
     return array_[i];
   }
 
   // Get a pointer to the zeroth element of the current object.
   // If there is no current object, return NULL.
   C* get() const {
+    D_BOOK_CRITICAL_SECTION(scoped_array_);
     return array_;
   }
 
   // Comparison operators.
   // These return whether two scoped_array refer to the same object, not just to
   // two different but equal objects.
-  bool operator==(C* p) const { return array_ == p; }
-  bool operator!=(C* p) const { return array_ != p; }
+  bool operator==(C* p) const { 
+    D_BOOK_CRITICAL_SECTION(scoped_array_);
+    return array_ == p; 
+  }
+  bool operator!=(C* p) const { 
+    D_BOOK_CRITICAL_SECTION(scoped_array_);
+    return array_ != p; 
+  }
 
   // Swap two scoped arrays.
   void swap(scoped_array& p2) {
+    D_BOOK_CRITICAL_SECTION(scoped_array_);
     C* tmp = array_;
     array_ = p2.array_;
     p2.array_ = tmp;
   }
 
   // Release an array.
   // The return value is the current pointer held by this object.
   // If this object holds a NULL pointer, the return value is NULL.
   // After this operation, this object will hold a NULL pointer,
   // and will not own the object any more.
   C* release() {
+    D_BOOK_CRITICAL_SECTION(scoped_array_);
     C* retVal = array_;
     array_ = NULL;
     return retVal;
   }
 
  private:
   C* array_;
 
   // Forbid comparison of different scoped_array types.
   template <class C2> bool operator==(scoped_array<C2> const& p2) const;
   template <class C2> bool operator!=(scoped_array<C2> const& p2) const;
 
   // Disallow evil constructors
   scoped_array(const scoped_array&);
   void operator=(const scoped_array&);
+
+  D_DEFINE_CRITICAL_SECTION(scoped_array_);
 };
 
 // Free functions
 template <class C>
 void swap(scoped_array<C>& p1, scoped_array<C>& p2) {
   p1.swap(p2);
 }
 
 template <class C>
 bool operator==(C* p1, const scoped_array<C>& p2) {
@@ skipping 33 matching lines @@
 
   // Destructor.  If there is a C object, call the Free functor.
   ~scoped_ptr_malloc() {
     free_(ptr_);
   }
 
   // Reset.  Calls the Free functor on the current owned object, if any.
   // Then takes ownership of a new object, if given.
   // this->reset(this->get()) works.
   void reset(C* p = NULL) {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     if (ptr_ != p) {
       free_(ptr_);
       ptr_ = p;
     }
   }
 
   // Get the current object.
   // operator* and operator-> will cause an assert() failure if there is
   // no current object.
   C& operator*() const {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     assert(ptr_ != NULL);
     return *ptr_;
   }
 
   C* operator->() const {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     assert(ptr_ != NULL);
     return ptr_;
   }
 
   C* get() const {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     return ptr_;
   }
 
   // Comparison operators.
   // These return whether a scoped_ptr_malloc and a plain pointer refer
   // to the same object, not just to two different but equal objects.
   // For compatibility wwith the boost-derived implementation, these
   // take non-const arguments.
   bool operator==(C* p) const {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     return ptr_ == p;
   }
 
   bool operator!=(C* p) const {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     return ptr_ != p;
   }
 
   // Swap two scoped pointers.
   void swap(scoped_ptr_malloc & b) {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     C* tmp = b.ptr_;
     b.ptr_ = ptr_;
     ptr_ = tmp;
   }
 
   // Release a pointer.
   // The return value is the current pointer held by this object.
   // If this object holds a NULL pointer, the return value is NULL.
   // After this operation, this object will hold a NULL pointer,
   // and will not own the object any more.
   C* release() {
+    D_BOOK_CRITICAL_SECTION(scoped_ptr_malloc_);
     C* tmp = ptr_;
     ptr_ = NULL;
     return tmp;
   }
 
  private:
   C* ptr_;
 
   // no reason to use these: each scoped_ptr_malloc should have its own object
   template <class C2, class GP>
   bool operator==(scoped_ptr_malloc<C2, GP> const& p) const;
   template <class C2, class GP>
   bool operator!=(scoped_ptr_malloc<C2, GP> const& p) const;
 
   static FreeProc const free_;
 
   // Disallow evil constructors
   scoped_ptr_malloc(const scoped_ptr_malloc&);
   void operator=(const scoped_ptr_malloc&);
+
+  D_DEFINE_CRITICAL_SECTION(scoped_ptr_malloc_);
 };
 
 template<class C, class FP>
 FP const scoped_ptr_malloc<C, FP>::free_ = FP();
 
 template<class C, class FP> inline
 void swap(scoped_ptr_malloc<C, FP>& a, scoped_ptr_malloc<C, FP>& b) {
   a.swap(b);
 }
 
 template<class C, class FP> inline
 bool operator==(C* p, const scoped_ptr_malloc<C, FP>& b) {
   return p == b.get();
 }
 
 template<class C, class FP> inline
 bool operator!=(C* p, const scoped_ptr_malloc<C, FP>& b) {
   return p != b.get();
 }
 
 #endif  // BASE_SCOPED_PTR_H_