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/video_coding/main/source/packet.cc

@@ -35,7 +35,7 @@ VCMPacket::VCMPacket()
 }
 
 VCMPacket::VCMPacket(const uint8_t* ptr,
-                     const uint32_t size,
+                     const size_t size,
                      const WebRtcRTPHeader& rtpHeader) :
     payloadType(rtpHeader.header.payloadType),
     timestamp(rtpHeader.header.timestamp),
@@ -57,7 +57,11 @@ VCMPacket::VCMPacket(const uint8_t* ptr,
     CopyCodecSpecifics(rtpHeader.type.Video);
 }
 
-VCMPacket::VCMPacket(const uint8_t* ptr, uint32_t size, uint16_t seq, uint32_t ts, bool mBit) :
+VCMPacket::VCMPacket(const uint8_t* ptr,
+                     size_t size,
+                     uint16_t seq,
+                     uint32_t ts,
+                     bool mBit) :
     payloadType(0),
     timestamp(ts),
     ntp_time_ms_(0),