Allow sending DependencyDescriptor rtp header extension in call

Bug: webrtc:10342
Change-Id: I8ccbc7381fc8ac436066f5b817fa32180fc8603e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/168542
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30546}
diff --git a/api/rtp_parameters.h b/api/rtp_parameters.h
index 01c6ed4..4f45d65 100644
--- a/api/rtp_parameters.h
+++ b/api/rtp_parameters.h
@@ -289,6 +289,7 @@
   // Experimental codec agnostic frame descriptor.
   static const char kGenericFrameDescriptorUri00[];
   static const char kGenericFrameDescriptorUri01[];
+  static const char kDependencyDescriptorUri[];
   // TODO(bugs.webrtc.org/10243): Remove once dependencies have been updated.
   static const char kGenericFrameDescriptorUri[];