Add MID sending to FlexfecSender

Bug: webrtc:4050
Change-Id: I1eefd99cca1c02751d3f5a2d3b57625ccb45323f
Reviewed-on: https://webrtc-review.googlesource.com/64321
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22811}
diff --git a/modules/rtp_rtcp/source/rtp_sender_unittest.cc b/modules/rtp_rtcp/source/rtp_sender_unittest.cc
index d769ec3..282e44a 100644
--- a/modules/rtp_rtcp/source/rtp_sender_unittest.cc
+++ b/modules/rtp_rtcp/source/rtp_sender_unittest.cc
@@ -980,10 +980,11 @@
   constexpr int kFlexfecPayloadType = 118;
   constexpr uint32_t kMediaSsrc = 1234;
   constexpr uint32_t kFlexfecSsrc = 5678;
+  const char kNoMid[] = "";
   const std::vector<RtpExtension> kNoRtpExtensions;
   const std::vector<RtpExtensionSize> kNoRtpExtensionSizes;
   FlexfecSender flexfec_sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
-                               kNoRtpExtensions, kNoRtpExtensionSizes,
+                               kNoMid, kNoRtpExtensions, kNoRtpExtensionSizes,
                                nullptr /* rtp_state */, &fake_clock_);
 
   // Reset |rtp_sender_| to use FlexFEC.
@@ -1038,11 +1039,12 @@
   constexpr int kFlexfecPayloadType = 118;
   constexpr uint32_t kMediaSsrc = 1234;
   constexpr uint32_t kFlexfecSsrc = 5678;
+  const char kNoMid[] = "";
   const std::vector<RtpExtension> kNoRtpExtensions;
   const std::vector<RtpExtensionSize> kNoRtpExtensionSizes;
 
   FlexfecSender flexfec_sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
-                               kNoRtpExtensions, kNoRtpExtensionSizes,
+                               kNoMid, kNoRtpExtensions, kNoRtpExtensionSizes,
                                nullptr /* rtp_state */, &fake_clock_);
 
   // Reset |rtp_sender_| to use FlexFEC.
@@ -1138,10 +1140,11 @@
   constexpr int kFlexfecPayloadType = 118;
   constexpr uint32_t kMediaSsrc = 1234;
   constexpr uint32_t kFlexfecSsrc = 5678;
+  const char kNoMid[] = "";
   const std::vector<RtpExtension> kNoRtpExtensions;
   const std::vector<RtpExtensionSize> kNoRtpExtensionSizes;
   FlexfecSender flexfec_sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
-                               kNoRtpExtensions, kNoRtpExtensionSizes,
+                               kNoMid, kNoRtpExtensions, kNoRtpExtensionSizes,
                                nullptr /* rtp_state */, &fake_clock_);
 
   // Reset |rtp_sender_| to use FlexFEC.
@@ -1201,10 +1204,11 @@
   constexpr int kFlexfecPayloadType = 118;
   constexpr uint32_t kMediaSsrc = 1234;
   constexpr uint32_t kFlexfecSsrc = 5678;
+  const char kNoMid[] = "";
   const std::vector<RtpExtension> kNoRtpExtensions;
   const std::vector<RtpExtensionSize> kNoRtpExtensionSizes;
   FlexfecSender flexfec_sender(kFlexfecPayloadType, kFlexfecSsrc, kMediaSsrc,
-                               kNoRtpExtensions, kNoRtpExtensionSizes,
+                               kNoMid, kNoRtpExtensions, kNoRtpExtensionSizes,
                                nullptr /* rtp_state */, &fake_clock_);
 
   // Reset |rtp_sender_| to use FlexFEC.