Revert some variables to uint32_t to fix compile errors on Mac gcc.
Revert some variables to uint32_t to fix compile errors on Mac gcc.

TBR=xians

Review URL: https://webrtc-codereview.appspot.com/1633004

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 569fdef7321cca192d2ed501ee857d8e2df4536a

sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc