RefCounted types should not have public destructors, delegate cleanup

remoting/client/frame_producer.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.
 
 #ifndef REMOTING_CLIENT_FRAME_PRODUCER_H_
 #define REMOTING_CLIENT_FRAME_PRODUCER_H_
 
 #include "base/callback_forward.h"
 #include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "third_party/skia/include/core/SkSize.h"
 
 namespace pp {
 class ImageData;
 } // namespace pp
 
 namespace remoting {
 
 class FrameProducer {
  public:
   FrameProducer() {}
-  virtual ~FrameProducer() {}
 
   // Adds an image buffer to the pool of pending buffers for subsequent drawing.
   // Once drawing is completed the buffer will be returned to the consumer via
   // the FrameConsumer::ApplyBuffer() call. Alternatively an empty buffer could
   // be returned via the FrameConsumer::ReturnBuffer() call.
   //
   // The passed buffer must be large enough to hold the whole clipping area.
   virtual void DrawBuffer(pp::ImageData* buffer) = 0;
 
   // Requests repainting of the specified |region| of the frame as soon as
   // possible. |region| is specified in output coordinates relative to
   // the beginning of the frame.
   virtual void InvalidateRegion(const SkRegion& region) = 0;
 
   // Requests returing of all pending buffers to the consumer via
   // FrameConsumer::ReturnBuffer() calls.
   virtual void RequestReturnBuffers(const base::Closure& done) = 0;
 
   // Notifies the producer of changes to the output view size or clipping area.
   // Implementations must cope with empty |view_size| or |clip_area|.
   virtual void SetOutputSizeAndClip(const SkISize& view_size,
                                     const SkIRect& clip_area) = 0;
 
+ protected:
+  virtual ~FrameProducer() {}
+
  private:
   DISALLOW_COPY_AND_ASSIGN(FrameProducer);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_CLIENT_FRAME_PRODUCER_H_