Objects that derive from RefCounted/RefCountedThreadSafe should not have public dtors.

base/message_pump_mac.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.
 
 // The basis for all native run loops on the Mac is the CFRunLoop.  It can be
 // used directly, it can be used as the driving force behind the similar
 // Foundation NSRunLoop, and it can be used to implement higher-level event
 // loops such as the NSApplication event loop.
 //
 // This file introduces a basic CFRunLoop-based implementation of the
@@ skipping 41 matching lines @@
 
 namespace base {
 
 class TimeTicks;
 
 class MessagePumpCFRunLoopBase : public MessagePump {
   // Needs access to CreateAutoreleasePool.
   friend class MessagePumpScopedAutoreleasePool;
  public:
   MessagePumpCFRunLoopBase();
-  virtual ~MessagePumpCFRunLoopBase();
 
   // Subclasses should implement the work they need to do in MessagePump::Run
   // in the DoRun method.  MessagePumpCFRunLoopBase::Run calls DoRun directly.
   // This arrangement is used because MessagePumpCFRunLoopBase needs to set
   // up and tear down things before and after the "meat" of DoRun.
   virtual void Run(Delegate* delegate) OVERRIDE;
   virtual void DoRun(Delegate* delegate) = 0;
 
   virtual void ScheduleWork() OVERRIDE;
   virtual void ScheduleDelayedWork(const TimeTicks& delayed_work_time) OVERRIDE;
 
  protected:
+  virtual ~MessagePumpCFRunLoopBase();
+
   // Accessors for private data members to be used by subclasses.
   CFRunLoopRef run_loop() const { return run_loop_; }
   int nesting_level() const { return nesting_level_; }
   int run_nesting_level() const { return run_nesting_level_; }
 
   // Return an autorelease pool to wrap around any work being performed.
   // In some cases, CreateAutoreleasePool may return nil intentionally to
   // preventing an autorelease pool from being created, allowing any
   // objects autoreleased by work to fall into the current autorelease pool.
   virtual NSAutoreleasePool* CreateAutoreleasePool();
@@ skipping 102 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(MessagePumpCFRunLoopBase);
 };
 
 class MessagePumpCFRunLoop : public MessagePumpCFRunLoopBase {
  public:
   MessagePumpCFRunLoop();
 
   virtual void DoRun(Delegate* delegate) OVERRIDE;
   virtual void Quit() OVERRIDE;
 
+ protected:
+  virtual ~MessagePumpCFRunLoop();
+
  private:
   virtual void EnterExitRunLoop(CFRunLoopActivity activity) OVERRIDE;
 
   // True if Quit is called to stop the innermost MessagePump
   // (innermost_quittable_) but some other CFRunLoopRun loop (nesting_level_)
   // is running inside the MessagePump's innermost Run call.
   bool quit_pending_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePumpCFRunLoop);
 };
 
 class MessagePumpNSRunLoop : public MessagePumpCFRunLoopBase {
  public:
   BASE_EXPORT MessagePumpNSRunLoop();
-  virtual ~MessagePumpNSRunLoop();
 
   virtual void DoRun(Delegate* delegate) OVERRIDE;
   virtual void Quit() OVERRIDE;
 
+ protected:
+  virtual ~MessagePumpNSRunLoop();
+
  private:
   // A source that doesn't do anything but provide something signalable
   // attached to the run loop.  This source will be signalled when Quit
   // is called, to cause the loop to wake up so that it can stop.
   CFRunLoopSourceRef quit_source_;
 
   // False after Quit is called.
   bool keep_running_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePumpNSRunLoop);
 };
 
 class MessagePumpNSApplication : public MessagePumpCFRunLoopBase {
  public:
   MessagePumpNSApplication();
 
   virtual void DoRun(Delegate* delegate) OVERRIDE;
   virtual void Quit() OVERRIDE;
 
+ protected:
+  virtual ~MessagePumpNSApplication();
+
  private:
   // False after Quit is called.
   bool keep_running_;
 
   // True if DoRun is managing its own run loop as opposed to letting
   // -[NSApplication run] handle it.  The outermost run loop in the application
   // is managed by -[NSApplication run], inner run loops are handled by a loop
   // in DoRun.
   bool running_own_loop_;
 
   DISALLOW_COPY_AND_ASSIGN(MessagePumpNSApplication);
 };
 
 class MessagePumpCrApplication : public MessagePumpNSApplication {
  public:
   MessagePumpCrApplication();
 
  protected:
+  virtual ~MessagePumpCrApplication() {}
+
   // Returns nil if NSApp is currently in the middle of calling
   // -sendEvent.  Requires NSApp implementing CrAppProtocol.
   virtual NSAutoreleasePool* CreateAutoreleasePool() OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(MessagePumpCrApplication);
 };
 
 class MessagePumpMac {
  public:
@@ skipping 18 matching lines @@
   // Requires NSApp to implement CrAppProtocol.
   BASE_EXPORT static bool IsHandlingSendEvent();
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(MessagePumpMac);
 };
 
 }  // namespace base
 
 #endif  // BASE_MESSAGE_PUMP_MAC_H_