Be able to build cast_unittest and related targets in Chrome tree

media/cast/audio_receiver/audio_decoder.h

Index: media/cast/audio_receiver/audio_decoder.h
diff --git a/media/cast/audio_receiver/audio_decoder.h b/media/cast/audio_receiver/audio_decoder.h
index 2f5f13aea2d710f98329573fd26cecc5fac3434b..bd84e37fbc83df9d66ebfb8398ef2cf8e91e4e8e 100644
--- a/media/cast/audio_receiver/audio_decoder.h
+++ b/media/cast/audio_receiver/audio_decoder.h
@@ -25,8 +25,6 @@ class AudioDecoder : public base::RefCountedThreadSafe<AudioDecoder> {
   explicit AudioDecoder(scoped_refptr<CastThread> cast_thread,
                         const AudioReceiverConfig& audio_config);
 
-  virtual ~AudioDecoder();
-
   // Extract a raw audio frame from the decoder.
   // Set the number of desired 10ms blocks and frequency.
   bool GetRawAudioFrame(int number_of_10ms_blocks,
@@ -39,9 +37,13 @@ class AudioDecoder : public base::RefCountedThreadSafe<AudioDecoder> {
                                int payload_size,
                                const RtpCastHeader& rtp_header);
 
+ protected:
+  virtual ~AudioDecoder();

[hubbe, 2013/09/26 23:03:20]

What's the point of making AudioDecoder virtual?
There are no virtual methods in this class, is there?

[Alpha Left Google, 2013/09/27 00:45:13]

This is necessary. This is a common problem with RefCountedThreadSafe.
RefCountedThreadSafe deletes an object when a ref goes to 0 using the type of
the base class, and in this case AudioDecoder. So the destructor has to be
virtual otherwise classes inherit from AudioDecoder will not have their dtor
executed properly.

+
  private:
-  // Can't use scoped_ptr due to protected constructor within webrtc.
-  webrtc::AudioCodingModule* audio_decoder_;
+  friend class base::RefCountedThreadSafe<AudioDecoder>;

[hubbe, 2013/09/26 23:03:20]

Why is this needed?

[Alpha Left Google, 2013/09/27 00:45:13]

This is chromium style. Chromium style wants a refcounted class to have
protected or private dtor, this is needed such that RefCountedThreadSafe can
delete this object.

+
+  scoped_ptr<webrtc::AudioCodingModule> audio_decoder_;
   bool have_received_packets_;
   scoped_refptr<CastThread> cast_thread_;
 
@@ -51,4 +53,4 @@ class AudioDecoder : public base::RefCountedThreadSafe<AudioDecoder> {
 }  // namespace cast
 }  // namespace media
 
-#endif  // MEDIA_CAST_AUDIO_RECEIVER_AUDIO_DECODER_H_
+#endif  // MEDIA_CAST_AUDIO_RECEIVER_AUDIO_DECODER_H_