Fork a few VideoReceiveStream related classes.

We'll need to deprecate the previous classes due to being used externally
as an API.

Bug: webrtc:11489
Change-Id: I64de29c8adae304d0b7628e24dd0abc5be6387ba
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/173960
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31136}
diff --git a/video/BUILD.gn b/video/BUILD.gn
index f8ad66b..28647df 100644
--- a/video/BUILD.gn
+++ b/video/BUILD.gn
@@ -22,6 +22,8 @@
     "quality_threshold.h",
     "receive_statistics_proxy.cc",
     "receive_statistics_proxy.h",
+    "receive_statistics_proxy2.cc",
+    "receive_statistics_proxy2.h",
     "report_block_stats.cc",
     "report_block_stats.h",
     "rtp_streams_synchronizer.cc",
@@ -42,14 +44,20 @@
     "transport_adapter.h",
     "video_quality_observer.cc",
     "video_quality_observer.h",
+    "video_quality_observer2.cc",
+    "video_quality_observer2.h",
     "video_receive_stream.cc",
     "video_receive_stream.h",
+    "video_receive_stream2.cc",
+    "video_receive_stream2.h",
     "video_send_stream.cc",
     "video_send_stream.h",
     "video_send_stream_impl.cc",
     "video_send_stream_impl.h",
     "video_stream_decoder.cc",
     "video_stream_decoder.h",
+    "video_stream_decoder2.cc",
+    "video_stream_decoder2.h",
   ]
 
   deps = [
@@ -507,6 +515,7 @@
       "quality_limitation_reason_tracker_unittest.cc",
       "quality_scaling_tests.cc",
       "quality_threshold_unittest.cc",
+      "receive_statistics_proxy2_unittest.cc",
       "receive_statistics_proxy_unittest.cc",
       "report_block_stats_unittest.cc",
       "rtp_video_stream_receiver_frame_transformer_delegate_unittest.cc",