Pass ownership of external encoders to the ACM

webrtc/modules/audio_coding/acm2/rent_a_codec.h

Index: webrtc/modules/audio_coding/acm2/rent_a_codec.h
diff --git a/webrtc/modules/audio_coding/acm2/rent_a_codec.h b/webrtc/modules/audio_coding/acm2/rent_a_codec.h
index dd2deceb8d326983b39a60777b31bd7993b1e6ce..d6f159a5b05398d8eb69c17ed94a60847f50cc77 100644
--- a/webrtc/modules/audio_coding/acm2/rent_a_codec.h
+++ b/webrtc/modules/audio_coding/acm2/rent_a_codec.h
@@ -197,15 +197,15 @@ class RentACodec {
   ~RentACodec();
 
   // Creates and returns an audio encoder built to the given specification.
-  // Returns null in case of error. The returned encoder is live until the next
-  // successful call to this function, or until the Rent-A-Codec is destroyed.
-  AudioEncoder* RentEncoder(const CodecInst& codec_inst);
+  // Returns null in case of error.
+  std::unique_ptr<AudioEncoder> RentEncoder(const CodecInst& codec_inst);

[hlundin-webrtc, 2016/03/08 13:29:24]

The name RentEncoder is no longer adequate, but I'll accept it anyway.

[kwiberg-webrtc, 2016/03/08 13:59:12]

Yeah, the class name isn't a good fit anymore either. But all these names are
going away soon-ish.

 
   struct StackParameters {
     StackParameters();
     ~StackParameters();
 
-    AudioEncoder* speech_encoder = nullptr;
+    std::unique_ptr<AudioEncoder> speech_encoder;
+
     bool use_codec_fec = false;
     bool use_red = false;
     bool use_cng = false;
@@ -218,10 +218,9 @@ class RentACodec {
 
   // Creates and returns an audio encoder stack constructed to the given
   // specification. If the specification isn't compatible with the encoder, it
-  // will be changed to match (things will be switched off). The returned
-  // encoder is live until the next successful call to this function, or until
-  // the Rent-A-Codec is destroyed.
-  AudioEncoder* RentEncoderStack(StackParameters* param);
+  // will be changed to match (things will be switched off). The speech encoder
+  // will be stolen.
+  std::unique_ptr<AudioEncoder> RentEncoderStack(StackParameters* param);
 
   // Creates and returns an iSAC decoder, which will remain live until the
   // Rent-A-Codec is destroyed. Subsequent calls will simply return the same