GTTF: Add missing virtual destructors.

base/prefs/public/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 24 matching lines @@
 #include "base/memory/ref_counted.h"
 #include "base/message_loop_proxy.h"
 #include "base/prefs/base_prefs_export.h"
 #include "base/prefs/pref_observer.h"
 #include "base/values.h"
 
 class PrefServiceBase;
 
 namespace subtle {
 
-class BASE_PREFS_EXPORT PrefMemberBase : public PrefObserver {
+class BASE_PREFS_EXPORT PrefMemberBase
+    : public NON_EXPORTED_BASE(PrefObserver) {
  public:
   // Type of callback you can register if you need to know the name of
   // the pref that is changing.
   typedef base::Callback<void(const std::string&)> NamedChangeCallback;
 
   PrefServiceBase* prefs() { return prefs_; }
   const PrefServiceBase* prefs() const { return prefs_; }
 
  protected:
   class BASE_PREFS_EXPORT Internal
@@ skipping 287 matching lines @@
 
 typedef PrefMember<bool> BooleanPrefMember;
 typedef PrefMember<int> IntegerPrefMember;
 typedef PrefMember<double> DoublePrefMember;
 typedef PrefMember<std::string> StringPrefMember;
 typedef PrefMember<FilePath> FilePathPrefMember;
 // This preference member is expensive for large string arrays.
 typedef PrefMember<std::vector<std::string> > StringListPrefMember;
 
 #endif  // BASE_PREFS_PUBLIC_PREF_MEMBER_H_