RefCounted types should not have public destructors

chrome/browser/managed_mode_unittest.cc

 // 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.
 
 #include "chrome/browser/managed_mode.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/bind.h"
@@ skipping 76 matching lines @@
   Browser browser_;
   StrictMock<MockBrowserWindow> window_;
   FakeManagedMode* managed_mode_;
 };
 
 class MockCallback : public base::RefCountedThreadSafe<MockCallback> {
  public:
   explicit MockCallback(FakeManagedMode* managed_mode)
       : managed_mode_(managed_mode) {
   }
-  virtual ~MockCallback() {}
 
   void CheckManagedMode(bool success) {
     EXPECT_EQ(managed_mode_->IsInManagedModeImpl(), success);
     DidEnterManagedMode(success);
   }
 
   MOCK_METHOD1(DidEnterManagedMode, void(bool));
 
+ protected:
+  virtual ~MockCallback() {}
+
  private:
+  friend class base::RefCountedThreadSafe<MockCallback>;
+
   FakeManagedMode* managed_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(MockCallback);
 };
 
 }  // namespace
 
 class ManagedModeTest : public ::testing::Test {
  public:
   ManagedModeTest() : ui_thread_(content::BrowserThread::UI, &message_loop_) {
@@ skipping 100 matching lines @@
 
 TEST_F(ManagedModeTest, Cancelled) {
   BrowserFixture managed_mode_browser(&managed_mode_, &managed_mode_profile_);
   BrowserFixture other_browser(&managed_mode_, &other_profile_);
 
   // If the user cancelled entering managed mode, it should fail immediately.
   managed_mode_.set_should_cancel_enter(true);
   managed_mode_.EnterManagedModeForTesting(&managed_mode_profile_,
                                            CreateExpectedCallback(false));
 }