Store a stacktrace of PrefService destruction in PrefChangeRegistrar

base/prefs/pref_member.h

 // Copyright (c) 2012 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.
 //
 // A helper class that stays in sync with a preference (bool, int, real,
 // string or filepath).  For example:
 //
 // class MyClass {
 //  public:
 //   MyClass(PrefService* prefs) {
@@ skipping 99 matching lines @@
   virtual void CreateInternal() const = 0;
 
   // See PrefMember<> for description.
   void Destroy();
 
   void MoveToThread(const scoped_refptr<base::MessageLoopProxy>& message_loop);
 
   // PrefObserver
   virtual void OnPreferenceChanged(PrefService* service,
                                    const std::string& pref_name) OVERRIDE;
+  // TODO(battre): Remove function (debugging tool for crbug.com/373435).
+  virtual void SetPrefServiceDestructionTrace(
+      const std::string& stacktrace) OVERRIDE;
 
   void VerifyValuePrefName() const {
     DCHECK(!pref_name_.empty());
   }
 
   // This method is used to do the actual sync with the preference.
   // Note: it is logically const, because it doesn't modify the state
   // seen by the outside world. It is just doing a lazy load behind the scenes.
   void UpdateValueFromPref(const base::Closure& callback) const;
 
   // Verifies the preference name, and lazily loads the preference value if
   // it hasn't been loaded yet.
   void VerifyPref() const;
 
   const std::string& pref_name() const { return pref_name_; }
 
   virtual Internal* internal() const = 0;
 
   // Used to allow registering plain base::Closure callbacks.
   static void InvokeUnnamedCallback(const base::Closure& callback,
                                     const std::string& pref_name);
 
  private:
   // Ordered the members to compact the class instance.
   std::string pref_name_;
   NamedChangeCallback observer_;
   PrefService* prefs_;
+  // TODO(battre): Remove attribute (debugging tool for crbug.com/373435).
+  std::string pref_service_destruction_;
 
  protected:
   bool setting_value_;
 };
 
 // This function implements StringListPrefMember::UpdateValue().
 // It is exposed here for testing purposes.
 bool BASE_PREFS_EXPORT PrefMemberVectorStringUpdate(
     const base::Value& value,
     std::vector<std::string>* string_vector);
@@ skipping 186 matching lines @@
 
 typedef PrefMember<bool> BooleanPrefMember;
 typedef PrefMember<int> IntegerPrefMember;
 typedef PrefMember<double> DoublePrefMember;
 typedef PrefMember<std::string> StringPrefMember;
 typedef PrefMember<base::FilePath> FilePathPrefMember;
 // This preference member is expensive for large string arrays.
 typedef PrefMember<std::vector<std::string> > StringListPrefMember;
 
 #endif  // BASE_PREFS_PREF_MEMBER_H_