Add incomplete ResourceAdaptationModuleInterface.

This interface will be improved upon iteratively to aid reviewability.
The initial version only handles starting and stopping the module; input
and output of the module is still implementation-specific.

TBR=sprang@webrtc.org

Bug: webrtc:11222
Change-Id: Ie307cfe3d3211c84346c035f2c0e9a632f58221b
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/162580
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Reviewed-by: Evan Shrubsole <eshr@google.com>
Cr-Commit-Position: refs/heads/master@{#30167}
diff --git a/video/BUILD.gn b/video/BUILD.gn
index 51cd40b..8cfbc94 100644
--- a/video/BUILD.gn
+++ b/video/BUILD.gn
@@ -203,6 +203,7 @@
     "../api/video:video_rtp_headers",
     "../api/video:video_stream_encoder",
     "../api/video_codecs:video_codecs_api",
+    "../call/adaptation:resource_adaptation",
     "../common_video",
     "../modules:module_api_public",
     "../modules/video_coding",