Use size_t more consistently for packet/payload lengths.

See design doc at https://docs.google.com/a/chromium.org/document/d/1I6nmE9D_BmCY-IoV6MDPY2V6WYpEI-dg2apWXTfZyUI/edit?usp=sharing for more information.

This CL was reviewed and approved in pieces in the following CLs:
https://webrtc-codereview.appspot.com/24209004/
https://webrtc-codereview.appspot.com/24229004/
https://webrtc-codereview.appspot.com/24259004/
https://webrtc-codereview.appspot.com/25109004/
https://webrtc-codereview.appspot.com/26099004/
https://webrtc-codereview.appspot.com/27069004/
https://webrtc-codereview.appspot.com/27969004/
https://webrtc-codereview.appspot.com/27989004/
https://webrtc-codereview.appspot.com/29009004/
https://webrtc-codereview.appspot.com/30929004/
https://webrtc-codereview.appspot.com/30939004/
https://webrtc-codereview.appspot.com/31999004/
Committing as TBR to the original reviewers.

BUG=chromium:81439
TEST=none
TBR=pthatcher,henrik.lundin,tina.legrand,stefan,tkchin,glaznev,kjellander,perkj,mflodman,henrika,asapersson,niklas.enbom

Review URL: https://webrtc-codereview.appspot.com/23129004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@7726 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/modules/audio_coding/neteq/test/NETEQTEST_RTPpacket.h

@@ -42,7 +42,7 @@ public:
     const webrtc::WebRtcRTPHeader* RTPinfo() const;
     uint8_t * datagram() const;
     uint8_t * payload() const;
-    int16_t payloadLen();
+    size_t payloadLen();
     int16_t dataLen() const;
     bool isParsed() const;
     bool isLost() const;
@@ -73,7 +73,7 @@ public:
     uint8_t *       _payloadPtr;
     int                 _memSize;
     int16_t         _datagramLen;
-    int16_t         _payloadLen;
+    size_t          _payloadLen;
     webrtc::WebRtcRTPHeader _rtpInfo;
     bool                _rtpParsed;
     uint32_t        _receiveTime;