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/sdk/BUILD.gn b/sdk/BUILD.gn
index 277a9a0..1158229 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -922,6 +922,7 @@
         "../api:libjingle_peerconnection_api",
         "../api:rtc_event_log_output_file",
         "../api:rtc_stats_api",
+        "../api:rtp_parameters",
         "../api:scoped_refptr",
         "../api/audio_codecs:audio_codecs_api",
         "../api/audio_codecs:builtin_audio_decoder_factory",