Only generate one CNAME per PeerConnection.

webrtc/pc/mediasession_unittest.cc

Index: webrtc/pc/mediasession_unittest.cc
diff --git a/webrtc/pc/mediasession_unittest.cc b/webrtc/pc/mediasession_unittest.cc
index 6ea7aeb8ab93f0b317e3b323acb88b9f39b15268..c13406d70210c7833d0097cc4d8b416d62a21cdb 100644
--- a/webrtc/pc/mediasession_unittest.cc
+++ b/webrtc/pc/mediasession_unittest.cc
@@ -1316,7 +1316,8 @@ TEST_F(MediaSessionDescriptionFactoryTest, TestCreateMultiStreamVideoOffer) {
   ASSERT_EQ(2U, updated_video_streams.size());
   EXPECT_EQ(video_streams[0], updated_video_streams[0]);
   EXPECT_EQ(kVideoTrack2, updated_video_streams[1].id);
-  EXPECT_NE(updated_video_streams[1].cname, updated_video_streams[0].cname);
+  // All the media streams in one PeerConnection share one cname
+  EXPECT_EQ(updated_video_streams[1].cname, updated_video_streams[0].cname);
 
   const StreamParamsVec& updated_data_streams = updated_dcd->streams();
   ASSERT_EQ(2U, updated_data_streams.size());
@@ -1435,7 +1436,7 @@ TEST_F(MediaSessionDescriptionFactoryTest, TestCreateMultiStreamVideoAnswer) {
   EXPECT_TRUE(dcd->rtcp_mux());                 // rtcp-mux defaults on
 
   // Update the answer. Add a new video track that is not synched to the
-  // other traacks and remove 1 audio track.
+  // other tracks and remove 1 audio track.
   opts.AddSendStream(MEDIA_TYPE_VIDEO, kVideoTrack2, kMediaStream2);
   opts.RemoveSendStream(MEDIA_TYPE_AUDIO, kAudioTrack2);
   opts.RemoveSendStream(MEDIA_TYPE_DATA, kDataTrack2);
@@ -1478,7 +1479,8 @@ TEST_F(MediaSessionDescriptionFactoryTest, TestCreateMultiStreamVideoAnswer) {
   ASSERT_EQ(2U, updated_video_streams.size());
   EXPECT_EQ(video_streams[0], updated_video_streams[0]);
   EXPECT_EQ(kVideoTrack2, updated_video_streams[1].id);
-  EXPECT_NE(updated_video_streams[1].cname, updated_video_streams[0].cname);
+  // All media streams in one PeerConnection share one cname
+  EXPECT_EQ(updated_video_streams[1].cname, updated_video_streams[0].cname);
 
   const StreamParamsVec& updated_data_streams = updated_dcd->streams();
   ASSERT_EQ(1U, updated_data_streams.size());