Enable probing with repeated payload packets by default.

webrtc/modules/rtp_rtcp/source/rtp_sender.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_sender.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
index cec7e17e4b621fbe7984281633db41d0793e19df..3d46009172a5a2f6fddf38b0db84eea63e804a06 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender.cc
@@ -569,8 +569,10 @@ size_t RTPSender::TrySendRedundantPayloads(size_t bytes_to_send) {
   return bytes_to_send - bytes_left;
 }
 
-size_t RTPSender::BuildPaddingPacket(uint8_t* packet, size_t header_length) {
-  size_t padding_bytes_in_packet = kMaxPaddingLength;
+size_t RTPSender::BuildPaddingPacket(uint8_t* packet,
+                                     size_t header_length,
+                                     size_t max_padding_length) {

[mflodman, 2015/09/08 12:33:51]

This could be named only padding_length, since we'll use this and it's not
really a max that we might send less than.

[stefan-webrtc, 2015/09/08 13:17:34]

Done.

+  size_t padding_bytes_in_packet = max_padding_length;

[mflodman, 2015/09/08 12:33:51]

No need for this variable.

[stefan-webrtc, 2015/09/08 13:17:34]

Done.

   packet[0] |= 0x20;  // Set padding bit.
   int32_t *data =
       reinterpret_cast<int32_t *>(&(packet[header_length]));
@@ -592,7 +594,7 @@ size_t RTPSender::TrySendPadData(size_t bytes) {
     CriticalSectionScoped cs(send_critsect_.get());
     timestamp = timestamp_;
     capture_time_ms = capture_time_ms_;
-    if (last_timestamp_time_ms_ > 0) {
+    if (rtx_ != kRtxOff && last_timestamp_time_ms_ > 0) {
       timestamp +=
           (clock_->TimeInMilliseconds() - last_timestamp_time_ms_) * 90;
       capture_time_ms +=
@@ -612,8 +614,10 @@ size_t RTPSender::SendPadData(uint32_t timestamp,
                              packet_router_;
   for (; bytes > 0; bytes -= padding_bytes_in_packet) {
     // Always send full padding packets.

[mflodman, 2015/09/08 12:33:51]

Can you extend this comment to indicate this is take care of by the budget and
we're not sending too much over time.

[stefan-webrtc, 2015/09/08 13:17:35]

Done.

-    if (bytes < kMaxPaddingLength)
-      bytes = kMaxPaddingLength;
+    size_t max_padding_length =
+        std::min(MaxDataPayloadLength(), kMaxPaddingLength);
+    if (bytes < max_padding_length)
+      bytes = max_padding_length;
 
     uint32_t ssrc;
     uint16_t sequence_number;
@@ -651,7 +655,8 @@ size_t RTPSender::SendPadData(uint32_t timestamp,
         CreateRtpHeader(padding_packet, payload_type, ssrc, false, timestamp,
                         sequence_number, std::vector<uint32_t>());
     assert(header_length != static_cast<size_t>(-1));
-    padding_bytes_in_packet = BuildPaddingPacket(padding_packet, header_length);
+    padding_bytes_in_packet =
+        BuildPaddingPacket(padding_packet, header_length, max_padding_length);
     assert(padding_bytes_in_packet <= bytes);
     size_t length = padding_bytes_in_packet + header_length;
     int64_t now_ms = clock_->TimeInMilliseconds();