Remove screen_share_config from the VideoConfig.

After the migration of the pc framework tests (https://webrtc-review.googlesource.com/c/src/+/174023), having "absl::optional<ScreenShareConfig> screen_share_config" field in VideoConfig became redundant. Replaced it with VideoTrackInterface::ContentHint content_hint field.

Bug: webrtc:11534
Change-Id: Ibf4b1c8daed95ef02111fe952171f11e290905d3
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/174702
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Andrey Logvin <landrey@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31187}
diff --git a/api/BUILD.gn b/api/BUILD.gn
index 1316e76..c14c412 100644
--- a/api/BUILD.gn
+++ b/api/BUILD.gn
@@ -362,6 +362,7 @@
     ":frame_generator_api",
     ":function_view",
     ":libjingle_peerconnection_api",
+    ":media_stream_interface",
     ":network_state_predictor_api",
     ":packet_socket_factory",
     ":simulated_network_api",