Update audio code to use size_t more correctly,

webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t.h

Index: webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t.h
diff --git a/webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t.h b/webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t.h
index 49df3c68be302ad8d4f6db0e1b76d963065115b7..344114dfdd53b34913561ab4f9e9f329a9ba4854 100644
--- a/webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t.h
+++ b/webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t.h
@@ -57,13 +57,13 @@ class AudioEncoderDecoderIsacT : public AudioEncoder, public AudioDecoder {
   int SampleRateHz() const override;
   int NumChannels() const override;
   size_t MaxEncodedBytes() const override;
-  int Num10MsFramesInNextPacket() const override;
-  int Max10MsFramesInAPacket() const override;
+  size_t Num10MsFramesInNextPacket() const override;
+  size_t Max10MsFramesInAPacket() const override;

[minyue-webrtc, 2015/07/31 14:10:14]

I would like to know what determines the choice between int and size_t：
unsigned/signed. 32bit/64bit, or other.

I see that some ints, e.g., the return of SampleRateHz and NumChannels remains
int, although they are supposedly also non-negative.

[Peter Kasting, 2015/08/04 02:02:52]

size_t should be used for byte or object counts, especially for things in
memory.  Counts of bytes, frames, and channels are all good candidates;
converting NumChannels to size_t is being done in a subsequent patch (so as to
avoid boiling the ocean).  SampleRateHz, by contrast, isn't an object count,
it's simply a numeric quantity, and per the Google style guide, things like that
should remain as ints (or int64_ts or whatever if necessary).  Basically, the
criteria is something to the effect of: what would the STL do?

[minyue-webrtc, 2015/08/04 07:31:50]

Fair enough

   int GetTargetBitrate() const override;
 
   // AudioDecoder methods.
   bool HasDecodePlc() const override;
-  int DecodePlc(int num_frames, int16_t* decoded) override;
+  size_t DecodePlc(size_t num_frames, int16_t* decoded) override;

[minyue-webrtc, 2015/07/31 14:10:14]

I know that DecodePlc may give non-negative return in current implementation.
But it may potentially return error codes as well, like DecodeInternal, (where
can people know an error otherwise).

[Peter Kasting, 2015/08/04 02:02:52]

If I'm converting this interface to size_t, it never returns a negative value,
even in error cases, in the current implementation.

   int Init() override;
   int IncomingPacket(const uint8_t* payload,
                      size_t payload_len,