New target for api/rtp_parameters.h and api/media_types.h.

The new target does not depend on libjingle_peerconnection_api, and to
do this, the named "audio" and "video" string literals had to be moved from
media_stream_interface.cc to media_types.cc.

In this cl, the dependency on libjingle_peerconnection_api can be
dropped from a few targets.

No-Presubmit: True
Bug: webrtc:8733
Change-Id: Icc675280d5c3c537f2255a9389ff18a482049921
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/53861
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28998}
diff --git a/api/media_stream_interface.cc b/api/media_stream_interface.cc
index 73566c4..e079079 100644
--- a/api/media_stream_interface.cc
+++ b/api/media_stream_interface.cc
@@ -9,11 +9,14 @@
  */
 
 #include "api/media_stream_interface.h"
+#include "api/media_types.h"
 
 namespace webrtc {
 
-const char MediaStreamTrackInterface::kVideoKind[] = "video";
-const char MediaStreamTrackInterface::kAudioKind[] = "audio";
+const char* const MediaStreamTrackInterface::kVideoKind =
+    cricket::kMediaTypeVideo;
+const char* const MediaStreamTrackInterface::kAudioKind =
+    cricket::kMediaTypeAudio;
 
 VideoTrackInterface::ContentHint VideoTrackInterface::content_hint() const {
   return ContentHint::kNone;