Fixing hidden dependencies.

Header files base/videosinkinterface.h and base/videosourceinterface.h
were not part of any target (because they cause 2 dependency cycles).

This CL uncomment them so GN can keep dependencies under control, the
2 dependency cycles will be removed as part of webrtc:6828.

Bug: webrtc:6828
Change-Id: I5c5580facc010ba619e105a9b8a572ac70169a01
Reviewed-on: https://webrtc-review.googlesource.com/27621
Reviewed-by: Patrik Höglund <phoglund@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20970}
diff --git a/call/BUILD.gn b/call/BUILD.gn
index 7404504..0b83d11 100644
--- a/call/BUILD.gn
+++ b/call/BUILD.gn
@@ -154,6 +154,12 @@
 }
 
 rtc_source_set("video_stream_api") {
+  # TODO(bugs.webrtc.org/6828): Remove dependency cycle:
+  # //call:video_stream_api ->
+  # //media:rtc_media_base ->
+  # //call:call_interfaces ->
+  # //call:video_stream_api
+  check_includes = false
   sources = [
     "video_config.cc",
     "video_config.h",