Add APIs to enable padding with redundant payloads.

Also makes a small change to the tests to remove flakiness. We can't do
BWE only based on rtp timestamps if we preemptively resend packets instead
of sending padding packets.

BUG=1812,2992
R=mflodman@webrtc.org, pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/15719004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@6400 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/video_engine/vie_rtp_rtcp_impl.h b/video_engine/vie_rtp_rtcp_impl.h
index 1702d63..5eec0ef 100644
--- a/video_engine/vie_rtp_rtcp_impl.h
+++ b/video_engine/vie_rtp_rtcp_impl.h
@@ -41,6 +41,7 @@
                              unsigned int CSRCs[kRtpCsrcSize]) const;
   virtual int SetRtxSendPayloadType(const int video_channel,
                                     const uint8_t payload_type);
+  virtual int SetPadWithRedundantPayloads(int video_channel, bool enable);
   virtual int SetRtxReceivePayloadType(const int video_channel,
                                        const uint8_t payload_type);
   virtual int SetStartSequenceNumber(const int video_channel,