Delete media transport integration.

MediaTransport is deprecated and the code is unused.

No-Try: True
Bug: webrtc:9719
Change-Id: I5b864c1e74bf04df16c15f51b8fac3d407331dcd
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/160620
Commit-Queue: Bjorn Mellem <mellem@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Reviewed-by: Åsa Persson <asapersson@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29923}
diff --git a/audio/audio_send_stream_unittest.cc b/audio/audio_send_stream_unittest.cc
index 6d6ec6a..95d7f73 100644
--- a/audio/audio_send_stream_unittest.cc
+++ b/audio/audio_send_stream_unittest.cc
@@ -144,7 +144,7 @@
   ConfigHelper(bool audio_bwe_enabled, bool expect_set_encoder_call)
       : clock_(1000000),
         task_queue_factory_(CreateDefaultTaskQueueFactory()),
-        stream_config_(/*send_transport=*/nullptr, MediaTransportConfig()),
+        stream_config_(/*send_transport=*/nullptr),
         audio_processing_(new rtc::RefCountedObject<MockAudioProcessing>()),
         bitrate_allocator_(&limit_observer_),
         worker_queue_(task_queue_factory_->CreateTaskQueue(
@@ -347,8 +347,7 @@
 }  // namespace
 
 TEST(AudioSendStreamTest, ConfigToString) {
-  AudioSendStream::Config config(/*send_transport=*/nullptr,
-                                 MediaTransportConfig());
+  AudioSendStream::Config config(/*send_transport=*/nullptr);
   config.rtp.ssrc = kSsrc;
   config.rtp.c_name = kCName;
   config.min_bitrate_bps = 12000;
@@ -367,7 +366,7 @@
       "{rtp: {ssrc: 1234, extmap-allow-mixed: true, extensions: [{uri: "
       "urn:ietf:params:rtp-hdrext:ssrc-audio-level, id: 2}], "
       "c_name: foo_name}, rtcp_report_interval_ms: 2500, "
-      "send_transport: null, media_transport_config: {media_transport: null}, "
+      "send_transport: null, "
       "min_bitrate_bps: 12000, max_bitrate_bps: 34000, "
       "send_codec_spec: {nack_enabled: true, transport_cc_enabled: false, "
       "cng_payload_type: 42, payload_type: 103, "