Update audio code to use size_t more correctly,

webrtc/modules/audio_coding/codecs/pcm16b/include/audio_encoder_pcm16b.h

 /*
  *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 13 matching lines @@
     Config() : AudioEncoderPcm::Config(107), sample_rate_hz(8000) {}
     bool IsOk() const;
 
     int sample_rate_hz;
   };
 
   explicit AudioEncoderPcm16B(const Config& config)
       : AudioEncoderPcm(config, config.sample_rate_hz) {}
 
  protected:
-  int16_t EncodeCall(const int16_t* audio,
-                     size_t input_len,
-                     uint8_t* encoded) override;
+  size_t EncodeCall(const int16_t* audio,
+                    size_t input_len,
+                    uint8_t* encoded) override;
 
   int BytesPerSample() const override;
 };
 
 struct CodecInst;
 
 class AudioEncoderMutablePcm16B
     : public AudioEncoderMutableImpl<AudioEncoderPcm16B> {
  public:
   explicit AudioEncoderMutablePcm16B(const CodecInst& codec_inst);
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_MODULES_AUDIO_CODING_CODECS_PCM16B_INCLUDE_AUDIO_ENCODER_PCM16B_H_