Enable audio streams to send padding.

webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
index e0bcebda158d2beaf3b22fec6b592d6a54d845a7..d1f70ee6f00e3a78dd942fe02e3fdde554b7f425 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_rtcp_impl.cc
@@ -617,6 +617,15 @@ int32_t ModuleRtpRtcpImpl::DeregisterSendRtpHeaderExtension(
   return rtp_sender_.DeregisterRtpHeaderExtension(type);
 }
 
+bool ModuleRtpRtcpImpl::HasBweExtensions() const {
+  return rtp_sender_.IsRtpHeaderExtensionRegistered(
+             kRtpExtensionTransportSequenceNumber) ||
+         rtp_sender_.IsRtpHeaderExtensionRegistered(
+             kRtpExtensionAbsoluteSendTime) ||
+         rtp_sender_.IsRtpHeaderExtensionRegistered(
+             kRtpExtensionTransmissionTimeOffset);
+}
+
 // (TMMBR) Temporary Max Media Bit Rate.
 bool ModuleRtpRtcpImpl::TMMBR() const {
   return rtcp_sender_.TMMBR();